I 

Practical 
Irrigation  and  Pumping 

Water  Requirements,  Methods  of  Irrigation 
and  Analyses  of  Cost  and  Profit 


BY 

BURTON   P.  FLEMING,  M.E. 

Associate  Member  American  Society  Civil  Engineers;  Head  of  Department  of  Me- 
chanical Engineering,  State  University  of  Iowa ;  formerly  Irrigation  Engineer, 
Office  Irrigation  Investigations,  U.  S.  Department  of  Agriculture 


FIRST    EDITION 
FIRST  THOUSAND 


NEW  YORK 
JOHN  WILEY  &  SONS,  INC. 

LONDON:    CHAPMAN    &    HALL,    LIMITED 
1915 


Copyright,  1915,  by 
BURTON  P.   FLEMING 


PUBLISHERS  PRINTING  COMPANY 
207-217  West  Twenty-fifth  Street,  New  York 


ACKNOWLEDGMENT 

The    following   firms   have    kindly    extended    the   use   of   cuts   for 
illustrations: 

American  Well  Works,  Aurora,  111. 

Buffalo  Steam  Pump  Co.,  Buffalo,  N.  Y. 

Byron  Jackson  Machine  Works,  San  Francisco,  Cal. 

De  La  Vergne  Machine  Works,  New  York,  N.  Y. 

Fairbanks  Morse  &  Co.,  Chicago,  111. 

Keystone  Driller  Co.,  Beaver  Falls,  Pa. 

Stover  Engine  Works,  Freeport,  111. 


111 


CONTENTS 

PAGE 

INTRODUCTORY  NOTE vii 

CHAPTER  I 
THE  AMOUNT  OF  WATER  REQUIRED i 

The  difficulties  in  the  solution  of  the  problem.  Amount 
used  affected  by  skill  of  irrigator.  Amounts  of  water  actually 
used.  Periods  of  irrigation  for  different  crops.  Amount  of 
water  used  at  each  irrigation.  Best  size  of  irrigating  stream. 
Acres  per  day  irrigated.  Amount  of  pumped  water  to  allow 
per  acre.  Dry-farming  methods  an  aid  to  irrigation. 

CHAPTER  II 

SOURCES  OF  SUPPLY n 

Legal  considerations  surrounding  use  of  surface  sources. 
Adequacy  of  supply,  surface  sources.  Legal  considerations, 
underground  sources.  Adequacy  of  underground  supply. 
Geology  of  deep  wells.  Geology  of  shallow  wells. 

CHAPTER   III 
THE  FLOW  OF  UNDERGROUND  WATER 20 

The  rate  of  flow.  The  ground-water  surface.  The  draw- 
down. Theory  of  flow  into  driven  wells.  Equation  of  time 
of  pumping.  Limitations  of  formulae.  Interference  of  wells. 
Practical  limits  of  draw-down.  Size  of  well  tube. 

CHAPTER   IV 

STRAINERS 37 

Definition.  Special  cases  governing  depth  of  strainers. 
Kinds  of  strainers.  Conclusions  on  strainers. 

CHAPTER  V 
WELL  SINKING -45 

Practical  suggestions.  Well-drilling  machinery.  Spudding 
machines.  Jetting  machines.  Rotary  machines.  Operation 
of  well-sinking.  The  well  pit.  Weights  of  pipe.  Tapering  of 
borings.  Stove  pipe  casing. 


VI  CONTENTS 

CHAPTER  VI 

PAGE 

PUMPS,  PUMPING  MACHINERY,  AND  APPLIANCES 58 

Caution  needed  in  selection  of  pumps.  Pumps  which  have 
been  proposed.  What  should  decide  make  and  type  of  pump 
to  use.  Standard  types  of  irrigation  pumps. 

CHAPTER  VII 

CENTRIFUGAL  PUMPS 63 

The  centrifugal  pump  described.  Specifications  for  centri- 
fugal pumps.  Characteristics  of  centrifugal  pumps.  What 
the  plant  designer  or  operator  must  know.  The  efficiency  of 
the  pump.  Pump  curves.  The  selection  of  a  pump.  Size 
of  engine  or  motor.  Pump  builders'  diagrams.  Pump  equa- 
tions. Locations  and  conditions  suitable  for  centrifugal 
pumps. 

CHAPTER  VIII 

DIFFERENT  TYPES  OF  INSTALLATION  FOR  CENTRIFUGAL  PUMPS  .   108 

Plant  No.  i.  Friction  effects  and  example.  Drive.  Prim- 
ing. Ejector  primer.  Discharge  pipe.  Water  hammer. 
Fittings.  Pump. 

Plant  No.  2.  Pump  pit  and  arrangement  of  belt  drive. 
Well  pipe  and  strainer.  Pump  foundation.  Fittings.  Drive. 

Plant  No.  3.  Advantages.  Pump  and  motor  speeds. 
Wiring.  Attention  required.  Electric  drive  the  ideal 
arrangement. 

Plant  No.  4.     Application  of  the  low-lift  plant. 

Plant  No.  5.  Suspension  frame.  Step  bearing  and  end 
thrust.  Stages.  Priming.  Discharge  pipe  and  details. 
Driving  pulley. 

Plant   No.    6.     Vertical   electric    drive. 

Means  of  water  measurement. 

CHAPTER   IX 
TYPICAL  PLANTS  NOT  USING  CENTRIFUGAL  PUMP 130 

The  question  of  sand.  Duplex  and  triplex  pumps.  Capac- 
ity limited.  Advantages  and  efficiency.  Vertical  rods.  Deep- 
well  pumps.  Speed.  Drive.  Important  details. 

CHAPTER  X 
COST  OF  PUMPING 135 

Importance  of  knowledge  of  pumping  costs.  Plant  owners' 
statements  unreliable.  Factors  affecting  cost  of  pumping, 
(i)  Cost  of  power.  Head  and  quantity  pumped  determine 
power  requirement.  Steam.  Gasoline.  Crude  oil  and  dis- 
tillates. Producer  gas.  Electricity.  (2)  Interest  on  first  cost 
of  plant  and  depreciation.  (3)  Maintenance  and  repairs. 
(4)  Attendance. 


CONTENTS  VU 

CHAPTER  XI 

PAGE 

THE  QUESTION  OF  COST  AND  PROFIT  ON  A  SMALL  FARM  IRRIGATED 

BY  PUMPED  WATER 152 

Elements  of  the  problem.  A  fair  estimate  of  yield.  Cost 
of  crop  production.  Shipping  costs  and  market  rates.  Money 
rates,  etc.  Demonstration  of  a  problem. 

CHAPTER  XII 

RESERVOIRS 160 

Their  necessity.  Water  tightness.  Construction.  Rodents. 
Capacity.  Depth. 

CHAPTER  XIII 

PRIME  MOVERS 165 

Steam  engines  and  boilers.  Throttle-governed  engines. 
Fly-wheel  governor  engines.  Boilers.  Auxiliaries  and  fittings. 
Boiler  insurance.  Gasoline  engines.  Difficulties  in  opera- 
tion. Over-rating.  Oil  fuels.  Distillate  engines. 

The  gas  producer  and  engine.     Principles  of  operation. 
Conditions  warranting  adoption  of  gas-producer  plant. 

Electric  motor  drive. 

CHAPTER  XIV 
THE  CENTRAL  STATION  PUMPING  PLANT      .     .     .     .     .     .     .185 

Locations  suitable  for  central  station  plants.  Conditions 
governing  feasibility,  (a)  Adequacy  of  supply,  (b)  Head. 
(c)  Suitability  of  tract  for  agricultural  purposes,  (d)  Ship- 
ping and  marketing  facilities,  (e)  Size  and  shape  of  tract, 
(f)  Ownership,  (g)  Possibilities  of  co-operation,  (h)  Fuels 
and  prices. 

Pumping  season. 

CHAPTER  XV 

WINDMILLS 197 

The  field  of  the  windmill  in  irrigation.  Kinds.  Size. 
Governing.  Selection  of  a  mill.  Power  of  a  mill,  wind 
records,  and  power  diagrams.  The  problem  of  determining 
best  size  of  pump  cylinder,  concrete  case.  Size  of  pump  for 
direct-acting  mill.  Size  of  pump  for  geared  mills.  The 
pump  cylinder. 


INTRODUCTORY  NOTE 

To  people  living  anywhere  on  the  American  continent 
west  of  the  hundredth  meridian,  the  practice  of  irrigation 
as  a  fundamental  necessity  in  the  production  of  crops  is  so 
common  a  matter  and  so  thoroughly  a  part  of  their  daily 
observation  and  experience,  that  they  scarcely  appreciate 
the  viewpoint  of  the  farmer  of  the  humid  regions,  who 
stands  more  or  less  aghast  at  the  idea  of  spending  a  large 
sum  per  acre  to  secure  for  the  growth  of  the  most  common 
crops  that  moisture  which  under  his  conditions,  nature 
itself  provides. 

The  author  does  not  agree  with  those,  who  in  the  at- 
tempt to  make  a  virtue  out  of  a  necessity,  go  so  far  as  to 
maintain  that  the  lack  of  moisture  which  makes  irrigation 
necessary  over  perhaps  one-third  of  the  area  of  the  United 
States  is  in  reality  a  blessing.  It  cannot  be  denied  that  the 
irrigation  farmer  of  the  west  cultivates  a  soil  in  which 
many  important  plant  foods,  leached  out  by  natural  rain- 
fall from  the  soils  of  the  more  humid  regions,  are  still 
retained,  making  it  in  general,  therefore,  a  rich  and  pro- 
ductive soil  when  water  is  applied;  he  is  not,  for  some 
years  at  least,  and  in  many  locations  never  will  be,  bothered 
by  the  drainage  problem;  he  enjoys  a  climate  in  which 
the  abundance  of  sunshine  makes  not  only  for  rapid  crop 
growth,  but  also  for  the  physical  well-being  of  himself  and 
family  while  most  important  of  all,  perhaps,  from  the 
standpoint  of  agronomy,  he  can  control  the  moisture 
supply  and  he  is  comparatively  free  from  those  seasonal 
variations  in  rainfall  and  temperature  which  make  farm- 
ing in  the  great  valley  of  the  Mississippi,  for  example, 


X  INTRODUCTORY  NOTE 

so  uncertain  an  enterprise.  On  the  other  hand,  it  can 
neither  be  denied  nor  evaded  that  these  advantages  are 
secured  and  the  region  made  habitable,  only  by  the  expen- 
diture of  comparatively  large  sums  of  money  in  developing 
the  natural  water  resources,  in  preparing  the  land  for  irri- 
gation and  applying  the  water.  All  of  these  expenses  the 
irrigation  farmer  must  bear  over  and  above  those  numerous 
and  sometimes  heavy  financial  burdens  attending  actual 
crop  production  in  more  humid  regions,  while  securing 
also  the  advantages  of  education,  public  improvements,  and 
the  protection  of  government.  This  additional  financial 
burden  under  which  the  irrigation  farmer  labors  is  therefore 
a  real  one,  and  that  he  bears  it  complacently,  is  able  to 
pay  a  comparatively  high  rate  of  interest  on  farm  mort- 
gages, finance  extensive  public  improvements,  such  as  good 
roads,  and  maintain  school  systems  quite  the  equal  of 
those  in  more  fully  settled  localities  in  the  humid  regions, 
is  evidence  that  the  advantages  accruing  through  irriga- 
tion, as  above  noted,  are  tangible  and  have  a  money-earning 
or  real  economic  value. 

The  cost  of  irrigation  is  enormous.  It  is  estimated 
by  the  census  of  1910  that  up  to  July  i  of  that  year,  about 
$308,000,000  had  been  spent  by  private  and  public  or 
quasi-public  enterprises  in  reclaiming  the  14,000,000  acres 
under  cultivation  by  irrigation  in  the  West.  It  is  this 
tremendous  investment,  simply  in  the  means  of  supplying 
moisture  for  growing  crops,  that  excites  the  wonder  of 
the  farmer  or  banker  of  the  humid  sections,  at  the  ability 
of  the  Western  communities  to  stand  the  strain,  for  under 
whatever  arrangement  the  various  irrigation  projects  are  or 
have  been  financed  it  must  not  be  forgotten  that  all  even- 
tually are  paid  for  by  the  products  of  irrigated  land.  Cer- 
tainly an  appreciation  of  the  meaning  of  the  figures  above 
cited,  should  impress  upon  the  Westerner  the  tremendous 


INTRODUCTORY   NOTE  XI 

importance  and  extent  of  the  subject  of  irrigation  which  he 
usually  takes  so  much  as  a  matter  of  course. 

The  sum  above  mentioned  has  been  spent  almost 
entirely  in  the  development  of  means  of  supplying  farms 
with  water  by  gravity  methods  of  distribution,  but  it  is 
significant  of  the  rapidity  with  which  development  is  pro- 
ceeding in  the  arid  West  that  the  pumping  of  water  for 
irrigation  purposes  is  attracting  more  and  more  attention 
each  year  and  already  it  is  estimated  that  250,000  H.P. 
of  pumping  engines  and  motors  are  engaged  in  this  work, 
that  nearly  $9,000,000  have  been  expended  in  the  necessary 
plants,  while  the  acreage  capable  of  being  irrigated  amounts 
to  over  260,000  acres. 

In  California  and  certain  other  sections  favorable  to 
the  growth  of  citrus  fruits  the  pumping  of  water  for  the 
irrigation  of  lands  not  otherwise  susceptible  of  irrigation 
has  been  a  common  practice  for  many  years  and  the  means 
and  appliances  have  been  well  worked  out.  In  other 
parts  of  the  West,  however,  it  is  only  comparatively  re- 
cently that  farmers  have  thought  seriously  of  attempting 
to  irrigate  on  a  commercial  scale  by  any  other  means  than 
that  of  conveying  surface  water  to  the  land  by  gravity. 
The  water  was  diverted  from  a  surface  stream  or  taken 
from  a  storage  reservoir.  Land  irrigated  or  susceptible  of 
irrigation  by  gravity  canals  has  become  in  the  course  of 
time  so  high  in  price,  or  so  scarce,  or  the  means  necessary 
for  gravity  irrigation  have  become  so  expensive,  that  at 
present  the  chance  is  very  small  for  the  man  of  strictly 
limited  resources  to  secure  a  foothold  in  any  of  those 
parts  of  the  West  already  well  developed.  There  still 
remain,  of  course,  vast  areas  of  land  whose  latent  agri- 
cultural possibilities  merely  wait  the  touch  of  water  to 
make  such  land  immensely  productive.  Much  of  it  lies 
either  on  the  higher  benches  or  mesas  adjacent  to  irrigated 


Xii  INTRODUCTORY   NOTE 

valleys  and  above  high-line  canals,  or  it  is  found  in  numer- 
ous localities  where  topographic  and  climatic  conditions 
preclude  the  presence  of  surface  streams.  Such  land,  in 
many  cases,  may  be  homesteaded,  or  if  in  private  owner- 
ship may  be  bought  at  prices  ranging  from  $5  to  $40  per 
acre,  depending  upon  how  successfully  it  or  other  lands  in 
the  neighborhood  have  been  "dry  farmed.77  Where  such 
land  has  beneath  it  a  water-bearing  formation,  and  general 
economic  conditions  are  favorable,  we  have  a  location 
suitable  for  the  profitable  development  of  a  scheme  of 
irrigation  by  pumping.  Other  locations  equally  favorable 
may  often  be  found  where  it  is  possible  to  pump  water  from 
a  high-line  canal  upon  land  lying  above  the  canal,  and  in 
other  cases,  where  a  long  and  expensive  canal  may  be  neces- 
sary to  reach  a  suitable  location  for  head-works,  a  careful 
study  of  the  problem  may  show  that  a  decided  saving  in 
first  cost  and  operation  as  well  as  maintenance,  will  result 
from  the  installation  and  operation  of  a  pumping  plant  to 
place  water  upon  high-lying  land  adjacent  to  a  surface 
stream.  Particularly  may  this  be  so  if  there  is  a  possi- 
bility of  generating  the  power  necessary  for  pumping  at 
some  near-by  point  where  the  conditions  favor  an  inex- 
pensive hydro-electric  development  and  transmitting  the 
power  thus  developed  to  the  most  feasible  location  for  the 
pumping  plant.  It  is  not  improbable  that,  if  there  were 
any  assurance  that  the  necessary  skilled  attendance  for 
such  a  plant  would  be  always  provided,  it  would  pay  some 
irrigation  concerns  with  which  the  writer  is  familiar  to 
abandon  their  present  long  and  costly  canal  lines,  now  so 
difficult  to  maintain,  install  a  pumping  plant  and  either 
buy  the  necessary  power  or  build  a  simple  hydro-electric 
plant  themselves.  If  properly  installed  and  maintained 
such  plants  would  be  sure  to  obviate  those  serious  losses 
frequently  sustained  through  canal  breaks,  which  are  a 


INTRODUCTORY   NOTE 


Xlll 


common  occurrence  in  the  very  midst  of  the  irrigation 
season,  on  canals  located  in  canyons  with  very  steep  cross 
slopes  and  in  unstable  or  porous  material. 

In  this  connection,  it  may  be  stated  that  a  remarkable 
development  has  occurred  within  the  past  few  years  in  the 
installation  of  irrigation  pumping  plants  in  Idaho  and 
Oregon,  along  the  Snake  River,  where,  because  of  its  slope 


FIG.  1. — A  high-grade  pumping  plant  on  the  Snake  River,  eastern  Oregon. 
This  plant  is  supplied  with  current  at  66,000  volts  and  has  eight  motors  of  total  capacity 
of  1,150  horse-power  driving  centrifugal  pumps  with  aggregate  working  capacity 
(normally  five  pumps  in  operation)  of  over  22,000  gallons  per  minute.  The  water  is 
raised  to  three  elevations,  55,  84,  and  110  feet  above  the  supply  canal  which  conveys 
water  to  the  plant  about  3,600  feet  inland  from  the  river.  This  plant  exhibits  probably 
the  most  advanced  example  of  mechanical  design  in  irrigation  work  in  the  West. 

and  the  configuration  of  the  valley,  gravity  systems 
are  very  expensive.  Electrical  power  is  being  generat- 
ed in  large  amounts  on  the  river  and  its  tributaries  by 
several  competing  companies  and  is  sold  at  from  $20  to 
$28  per  horse-power  for  the  irrigation  season.  Several  very 
large  electrically  driven  plants  have  recently  been  con- 


x]v  INTRODUCTORY   NOTE 

structed  which  pump  water  from  the  river  upon  lands 
lying  as  much  as  150  feet  above,  and  in  areas  as  large  as 
15,000  acres,  requiring  as  much  as  3,000  H.P.  in  one  plant. 
In  the  vicinity  of  Payette,  Idaho,  a  very  unusual  develop- 
ment of  this  phase  of  irrigation  is  found,  there  being  about 
1 60  plants  in  a  length  of  20  miles  along  the  river,  utilizing 
from  2  to  1,000  H.P.  each.  A  large  number  of  the  plants 
lift  water  from  a  high-line  canal  upon  orchard  lands  lying 
above  the  canal,  while  others  divert  directly  from  the  river. 
Nearly  all  of  these  plants  have  electrically  driven  centrifugal 
pumps  and  many  fine  fruit  ranches  depend  entirely  upon 
them  for  water  supply. 

Before  any  decision  can  or  should  be  reached  with 
regard  to  the  feasibility  of  a  pumping-plant  project,  a 
careful  and  systematic  study  should  be  made  of  the  matter 
in  all  its  phases.  This  applies  to  the  small  individual 
plant  as  well  as  to  the  large  central  plant,  perhaps  with 
greater  force  to  the  former  since  such  plants  often  represent 
the  entire  working  capital  of  an  individual  who  stakes  his 
future  upon  the  success  of  his  venture.  Ill-considered 
plans,  wrong  and  costly  types  of  machinery,  too  high  a 
"pumping  head,"  and  a  disregard  of  such  simple  factors  as 
nearness  to  markets  and  suitable  crops  to  grow  with  high- 
priced  water  have  contributed,  in  the  many  cases  which 
have  come  under  the  writer's  observation,  to  the  lack  of 
success  attending  a  pumping-plant  investment.  It  is  not 
enough  that  there  shall  be  cheap  land  and  a  water-bearing 
stratum  beneath  it,  or  some  other  adjacent  source  of  water 
supply.  This  water  must  not  be  at  great  depth  below  the 
surface  to  be  irrigated  or  the  source  be  so  far  away  that 
long  pipe  lines  are  required;  otherwise  it  will  not  pay  with 
any  ordinary  crop  to  develop  the  water  supply,  however 
extensive  or  unfailing  it  may  be.  The  crop  grown  must  in 
any  case  be  one  requiring  relatively  little  water,  and  must 


INTRODUCTORY  NOTE  XV 

give  high  crop  value  per  acre,  while  the  machinery  used 
should  be  of  such  type  as  will  give  the  service  desired  with 
a  maximum  of  running  economy  and  a  minimum  of  main- 
tenance charges. 

It  will  be  the  endeavor  of  the  writer  in  the  present 
volume,  to  consider  the  irrigation  problem  chiefly  from 
the  pumping  standpoint,  treating  of  those  matters  which 
interest  the  man  considering  the  installation  of  a  small 
pumping  plant  from  both  the  standpoints  of  design  and 
operation.  It  is  hoped  further  that  the  author's  suggestions 
will  be  helpful  to  the  contractor  who  specializes  in  the 
machinery  of  pumping  plants  and  be  of  some  assistance  to 
the  engineer  who  is  called  upon  to  design  the  central  station 
plant.  Beginning  with  estimates  of  water  requirements  of 
different  crops  on  different  soils  and  in  different  localities, 
the  writer  will  consider  in  turn:  the  matter  of  wells  and 
well-sinking;  pumps  and  pumping  machinery  suitable  for 
different  depths  and  volumes  together  with  typical  designs 
for  certain  assumed  conditions;  prime  movers  including  a 
discussion  of  oil  engines,  gas  producers,  etc.;  windmill  irri- 
gation, chiefly  from  standpoint  of  co-relation  between  wind 
velocities  and  pump  size;  the  question  of  cost  and  profit 
in  pumping  and  a  method  of  estimating  the  latter  for 
certain  conditions;  and,  finally,  the  central  station  plant  and 
its  possibilities.  An  attempt  will  be  made  to  make  the 
discussion  as  general  as  the  nature  of  the  subject  will  allow, 
but  where  specific  instances  or  trade  names  are  thought 
helpful  they  will  be  given. 

The  writer  brings  to  his  aid  in  the  preparation  of  this 
volume  an  experience  of  over  eight  years  in  irrigation  work, 
during  which  time  he  has  covered  most  of  the  Western 
States,  and  has  had  much  opportunity  to  observe  and  study 
irrigation  conditions.  He  has  had  the  benefit  of  consider- 
able direct  personal' experience  (some  of  it  rather  bitter, 


XVI  INTRODUCTORY  NOTE 

indeed)  in  the  matter  of  irrigation  pumping  and  on  several 
questions  connected  therewith  is  able  to  give  the  results 
of  experimental  work. 

The  writer  has  drawn  his  data  freely  from  government 
reports,  experiment  station  bulletins,  particularly  those 
written  by  himself,  and  various  other  sources  specifically 
mentioned  in  the  text. 


PRACTICAL   IRRIGATION 
AND   PUMPING 


CHAPTER  I 

THE  AMOUNT  OF  WATER  REQUIRED 

The  Difficulties  in  the  Solution  of  the  Problem.— A 

necessary  preliminary  to  the  consideration  of  any  problem 
in  the  water  supply  for  irrigation,  is  a  more  or  less  definite 
knowledge  of  the  amount  of  water  required  in  the  irrigation 
of  the  particular  crops  it  is  desired  to  grow  upon  the  par- 
ticular lands  it  is  desired  to  irrigate.  At  the  outset,  one  is 
confronted  with  a  difficulty  in  securing  definite  information 
upon  the  matter,  due  to  the  fact  that  most  of  the  data  we 
have  on  what  has  been  called  "The  duty  of  water,"  has 
been  obtained  by  investigations  made  on  gravity  systems. 
Except  under  exceptionally  well-managed  canal  systems, 
especially  those  where  the  water  user  is  charged  on  the 
basis  of  the  amount  used,  at  a  certain  price  per  acre-inch*  or 
acre-foot,*  there  is  always  a  temptation  for  the  irrigator  to 
use  more  water  than  is  really  necessary  because  it  costs  him 
little  or  nothing  and  he  usually  works  under  the  time- 
honored  delusion  that  "The  more  water  the  more  crop." 
Moreover,  most  measurements  have  been  taken  where  but 
little  or  no  attempt  has  been  made  to  eliminate  seepage 
losses  in  distribution,  and  where  but  little  attention  is  paid 

*  The  acre-inch  is  the  amount  of  water  which  without  loss  of  any 
sort  would  cover  a  level  area  of  one  acre  to  the  depth  of  one  inch.  The 
acre-foot  is  twelve  times  this  amount. 

I 


2      t.\      1ft  PRACTICAL  ^IRRIGATION  AND  PUMPING 

to  the  prevention  of  loss  through  leaky  and  imperfect 
ditches  or  field  laterals.  Consequently  results  obtained 
under  these  conditions  are  not  to  be  considered  comparable 
with  those  bound  to  follow  when  the  irrigator  realizes  that 
every  revolution  of  the  pump  by  which  the  water  is  raised, 
represents  a  definite  amount  to  be  deducted  from  the 
returns  of  the  crop  grown  and  where  consequently  we  are 
apt  not  to  find  pumped  water  escaping  from  fields  into 
adjacent  roadways  or  pouring  through  breaks  in  poorly 
built  laterals  while  the  irrigator  discusses  politics  with  his 
neighbor.  Although  therefore,  so  far  as  the  crops  them- 
selves are  concerned,  the  water  requirement  is  the  same 
whatever  the  source  of  the  water  supply  or  the  method  of 
distribution,  the  human  element  which  enters  into  the 
problem  makes  it  possible  in  estimates  to  allow  a  very 
much  higher  duty  for  pumped  water  than  for  water  de- 
rived from  surface  sources.  If  in  connection  with  the 
pumping  plant  a  reservoir  is  used  and  losses  in  distribution 
are  prevented  by  employing  pipe  or  concrete  distributaries 
and  if,  also,  great  care  is  observed  in  laying  out  the  fields 
in  such  a  way  as  to  reduce  evaporation  and  needless  seepage 
to  a  minimum,  the  amount  of  water  needed  for  a  crop  may 
be  but  little  more  than  its  absolute  water  requirement. 

Amount  Used  Affected  by  Skill  of  Irrigator. — The  amounts 
of  water  found  to  be  used  in  the  irrigation  of  crops,  when 
supplied  by  the  gravity  systems,  present  considerable  varia- 
tions in  different  localities  due  to  differences  in  climatic 
conditions,  topography  as  affecting  surface  or  subterranean 
drainage,  soil  porosity,  the  character  of  distribution,  and 
finally  the  skill  of  the  irrigator.  It  is  the  opinion  of  the 
writer,  based  on  his  own  measurements  and  upon  observa- 
tions made  in  various  parts  of  the  West  under  considerable 
range  of  altitude  and  latitude,  that  the  irrigator's  skill  has 
probably  a  greater  effect  upon  duty  of  water  measurements 


THE   AMOUNT   OF   WATER  REQUIRED 


than  have  any  or  perhaps  all  of  the  other  conditions  men- 
tioned above.  That  is  to  say  that  a  careless  irrigator  in  a 
northern  climate  may  use  more  water  in  the  irrigation  of  a 
crop  grown  upon  a  dense  soil  than  would  a  careful  irrigator 
use  for  the  same  crop  on  a  deep  sandy  soil  in  the  intensely 
hot  valleys  of  New  Mexico  or  Arizona.  The  best  the 
engineer  can  do,  therefore,  especially  when  designing  a 
gravity  system,  is  to  base  his  estimates  upon  averages,  not 
forgetting  that  local  irrigation  customs  and  practices  may 
change  easily  the  values  subsequently  obtained  in  the 
practice  of  the  water  users  by  25  to  50  per  cent. 

Amounts  of  Water  Actually  Used. — The  writer  has 
measured  the  duty  of  water  on  fields  of  alfalfa  in  western 
Nebraska  and  southern  Wyoming  where  52  acre-inches 
per  acre  were  used  and  he  has  seen  abundant  alfalfa  crops 
grown  in  New  Mexico  with  40  inches.  Likewise  he  has 
also  observed  conditions  in  New  Mexico  where  irrigators 
thought  it  impossible  to  grow  a  crop  of  alfalfa  on  less  than 
60  acre-inches. 

In  the  following  table  are  given  limiting  values  of  the 
duty  of  water  from  various  crops  as  determined  in  different 
localities  with  gravity  systems. 

TABLE  I 

DUTY  OF  WATER,  VARIOUS  CROPS,  GRAVITY  SYSTEMS 
ACRE- INCHES  PER  ACRE 


Alfalfa 

Corn 

Wheat 

Oats 

Orchards 
Small  Fruits 

Garden 
Truck 
Patches 

36  to  60 

24  to  30 

18  to  26 

18  to  24 

18  to  20 

30  to  36 

The  quantities  in  the  table  are  based  upon  averages 
secured  by  measurements  made  at  the  edge  of  the  field. 
The  duty  at  head-gate  of  the  main  canal  will  increase  the 


4  PRACTICAL  IRRIGATION  AND  PUMPING 

above  values  by  30  to  50  per  cent,  due  to  seepage  and  evap- 
oration losses  in  distribution. 

Periods  of  Irrigation  for  Different  Crops. — Probably  as 
satisfactory  a  basis  of  estimate  as  it  is  possible  to  obtain  in 
figuring  upon  water  requirements  is  as  to  the  number  of 
times  a  crop  must  be  irrigated  and  the  probable  amount 
supplied  at  each  watering.  This  is  for  the  reason  that 
practice  in  regard  to  such  common  crops  as  are  included 
in  the  above  table  is  pretty  well  standardized,  and  the 
number  of  irrigations  necessary  or  desirable  will  not  be 
found  to  vary  appreciably  from  the  mean  for  any  given 
locality.  Thus  in  the  case  of  alfalfa, — in  the  northern 
climates  this  crop  will  make  two  and  sometimes  three 
cuttings;  in  the  southwest,  four  generally  and  sometimes 
five  cuttings  are  secured.  The  number  of  cuttings  is  also 
of  course  influenced  by  altitude.  The  common  practice  is 
to  give  this  crop  a  thorough  irrigation  at  the  beginning  of 
the  season  to  get  it  well  started,  a  second  previous  to  the 
first  cutting,  a  third  shortly  after  the  crop  has  been  removed, 
not  until  the  fresh  growth  has  attained  a  height  suffi- 
cient to  give  it  some  protection  against  excessive  evapora- 
tion and  scalding,  a  fourth  about  a  week  or  ten  days  before 
the  second  cutting,  and  so  on  for  each  succeeding  cutting. 
Thus  each  cutting  will  secure  at  least  two  irrigations,  or 
the  number  of  irrigations  will  be  about  double  the  number  of 
cuttings.  It  might  be  said  in  passing,  that  usually  in  the 
growing  of  alfalfa,  rainfall,  unless  most  unusual  in  amount, 
has  but  little  effect  upon  the  practice  of  irrigation,  and 
rarely  will  cause  the  irrigator  to  miss  a  regular  watering  or 
will  diminish  appreciably  the  amount  of  water  which  should 
be  used  during  a  perfectly  dry  season. 

Practice  in  regard  to  grain  crops  is  more  variable,  de- 
pending upon  locality,  amount  of  rainfall,  etc.  In  most 
cases  an  irrigation  is  necessary  either  just  before  or  imme- 


THE   AMOUNT   OF   WATER   REQUIRED  5 

diately  after  plowing  and  planting  in  order  that  moisture 
conditions  may  be  proper  for  germination.  A  second  irri- 
gation will  follow  possibly  at  the  end  of  two  weeks  or 
seventeen  days,  and  the  third  and  usually  the  final  is 
given  while  the  grain  is  in  the  milk.  An  extra  watering 
may  be  necessary  between  the  second  and  third  mentioned, 
in  the  absence  of  normal  summer  rains,  thus  giving  a 
minimum  of  three  and  a  maximum  of  four  irrigations  for 
wheat,  oats,  barley,  flax,  etc. 

Corn,  sorghum,  and  Kaffir  corn  are  crops  usually  re- 
quiring less  water  than  broad  culture  crops,  since  they  are 
cultivated  more  or  less  frequently,  thus  preventing  rapid  soil 
evaporation,  besides  which  there  soon  is  formed  in  the  process 
of  growth  a  dense  shade  further  reducing  soil  evaporation. 
Three  irrigations  are  usually  found  ample  for  such  crops. 

Orchards  require  less  water  per  acre  than  most  crops, 
due  to  the  fewer  number  of  plants  per  acre  and  to  the  fact 
that  greater  care  ordinarily  is  taken  in  distribution  in 
orchards.  Usually  three  and  not  to  exceed  five  irrigations 
are  given  and  the  tendency  is  towards  the  lower  limit  when 
proper  cultural  conditions  are  maintained. 

Truck  gardens,  owing  to  the  greater  sensitiveness  of  the 
plants  to  unfavorable  moisture  conditions,  must  be  irri- 
gated with  care  and  with  not  excessive  amounts  of  water. 
Thus,  although  the  truck  garden  may  need  to  be  irrigated 
over  the  entire  area  from  six  to  eight  times  or  possibly  more 
during  a  season,  yet  the  amount  of  water  used  will  probably 
be  less  than  that  required  for  a  broad  culture  crop  or  one 
which  is  deep-rooted. 

Amount  of  Water  at  Each  Irrigation. — Nothing  is  better 
known  by  the  irrigator  of  extensive  experience  than  that 
"it  does  not  pay"  to  use  a  small  stream  of  water  or  a 
"small  head  of  water"  in  irrigation.  A  small  stream  seems 
to  dissipate  and  lose  itself  when  one  attempts  to  spread  it 


6  PRACTICAL   IRRIGATION  AND   PUMPING 

over  an  extensive  area,  so  that  if  a  certain  volume  is  avail- 
able, as  for  example,  i  acre-foot,  it  might  be  found  im- 
possible to  spread  this  amount  uniformly  over  2  acres 
with  a  small  stream,  no  matter  how  carefully  the  land  had 
been  prepared  or  what  its  character.  On  the  other  hand, 
with '"a  good  irrigation  head"  as  he  would  call  it,  a  skilled 
irrigator  would  without  difficulty  distribute  the  acre-foot 
over  the  acre  and  probably  secure  great  uniformity  in  its 
distribution,  so  that  no  one  part  would  be  soaked  and 
another  part  be  left  practically  dry.  The  difficulty  in  dis- 
tribution may  be  said  to  increase  even  on  well-prepared 
land  as  the  total  quantity  applied  decreases.  Experiments 
conducted  by  the  writer  on  sandy  open  mesa  soil,  showed 
that  it  was  next  to  impossible  to  secure  uniform  distribution 
even  on  small  carefully  prepared  plats,  with  less  than  3 
acre-inches  of  water  per  acre  at  an  irrigation,  and  that  very 
much  greater  success  was  attained  when  4  acre-inches  were 
applied  at  an  irrigation. 

In  actual  experience  under  gravity  irrigation  systems 
where  water  is  used  with  but  little  thought  of  economy, 
5  and  6  acre-inches  are  usually  applied  per  acre  at  an  irri- 
gation of  alfalfa,  5  acre-inches  with  grains,  3  to  4  with 
orchards,  and  about  3  with  truck  patches.  It  will  be 
seen,  therefore,  that  in  general,  3  acre-inches  is  the  probable 
minimum  which  may  be  allowed  per  irrigation,  even  under 
the  careful  system  of  irrigation  which  must  be  assumed 
as  existing  or  will  exist  under  a  pumping  project,  and  for 
most  cases,  probably  4  acre-inches  would  represent  the 
value  attained  by  the  average  irrigator  even  when  im- 
pressed, as  every  one  using  pumped  water  should  be,  with 
the  supreme  necessity  for  economy  in  its  use. 

Best  Size  of  Irrigating  Stream. — Although,  as  suggested 
in  a  previous  paragraph,  a  small  "irrigating  head"  is  un- 
economical, on  the  other  hand,  large  streams  are  equally 


THE   AMOUNT   OF   WATER   REQUIRED  7 

conducive  to  waste  when  too  large  for  an  irrigator  to 
handle  properly.  The  size  of  stream  which  one  man  may 
handle,  will  be  determined  entirely  by  the  character  of  crop 
being  irrigated,  the  thoroughness  with  which  the  land  is 
prepared  for  irrigation,  its  slope,  and  the  character  of  the 
soil.  Each  of  these  conditions  is  more  or  less  dependent 
upon  the  other;  thus  with  a  grain  crop  the  same  care  in 
preparing  the  land  would  not  be  necessary  or  expected  as 
in  the  case  of  a  melon  crop.  However,  in  the  case  of  alfalfa 
or  grains,  where  well-defined  furrows  do  not  exist,  a  larger 
stream  could  be  used  to  advantage  than  would  be  desirable 
for  furrow  irrigation,  and  again  a  crop  on  land  carefully 
leveled  and  prepared,  could  be  irrigated  by  one  man  with 
a  larger  stream  flow  than  where  the  surface  is  so  uneven  as 
to  require  considerable  of  the  irrigator's  time  and  skill  to 
conduct  water  to  the  high  spots.  Also  on  sandy,  open 
soil,  one  man  could  handle  a  large  stream  to  less  advantage 
than  a  small  ofie,  due  to  the  greater  tendency  of  the  water, 
in  the  former  case,  toward  erosion  both  of  field  and  laterals, 
a  condition  not  existing  on  an  adobe  or  dense  loam  soil. 

In  general,  one  man  may  handle  streams  of  the  sizes 
given  by  the  following  table  on  different  soils  and  with  the 
special  methods  of  irrigation  pertaining  to  the  crops  indi- 
cated. 

TABLE  II 

MAXIMUM  NUMBER  OF  GALLONS  PER  MINUTE,  WHICH  ONE  MAN  MAY 
HANDLE  SUCCESSFULLY  IN  IRRIGATION 


Sandy  Soil 

Dense  or  Heavy  Soil 

Alfalfa 
Grains 
Orchard 
Truck  Garden 

450   60O 
400-500 
300-450 
250-300 

600-900 
500-700 
400-500 
300-350 

8 


PRACTICAL  IRRIGATION  AND  PUMPING 


The  minimum-sized  stream  with  which  a  man  may  do 
good  work  is  200  gallons  per  minute  under  usual  conditions, 
and  if  a  flow  no  greater  than  this  can  be  secured  from  a 
pumping  plant  it  will  be  better,  in  general,  to  store  several 
hours'  or  even  days'  supply  in  a  tight  reservoir  and  use  a 
large  stream  for  a  short  time  rather  than  attempt  to  accom- 
plish anything  with  so  small  a  stream.  The  question  of 
reservoirs  will  be  more  fully  considered  in  a  subsequent 
chapter. 

Acres  per  day,  Irrigated. — It  is  of  some  importance  in 
figuring  costs  of  irrigation  and  in  estimates  on  sizes,  to 
know  how  much  acreage  the  average  irrigator  may  cover 
with  irrigation  streams  of  different  sizes  when  applying 
various  quantities  per  acre.  The  following  diagram  will 
enable  this  to  be  determined  graphically. 


I- 

o 

a* 
§• 

2 

I 


?/ 


100 


800      800       400      500       600      700       800      900 
Size  of  Irrigating  Slream-gals./inhi. 


DIAGRAM   1 

SHOWING  THE  ACREAGE  WHICH  ONE  MAN  MAY  COVER  WITH 
IRRIGATING  STREAMS  OF  DIFFERENT  SIZES  AND  APPLYING  VARIOUS 
QUANTITIES 

It  will  be  noted  by  the  diagram  that  when  applying  4 
acre-inches  per  acre  with  a  poo-gallon-per-minute stream,  one 


THE   AMOUNT   OF   WATER   REQUIRED  9 

man  may  cover  nearly  5  acres.  This  acreage  is  to  be  con- 
sidered about  the  average  maximum  performance  of  one 
man  on  well-prepared  ground  and  the  table  will  be  found 
to  correspond  with  the  experience  of  practical  irrigators 
generally,  though  some  variation  is  to  be  expected  according 
to  local  conditions. 

Amount  of  Pumped  Water  to  Allow  per  Acre. — Sum- 
marizing what  has  been  said  in  previous  paragraphs,  we 
may  state  the  case  briefly  as  follows : 

1.  Pumped  water  will  be  used  with  greater  care 

than  water  supplied  by  gravity  because  of 
its  recognized  greater  cost. 

2.  For  a  successful  practice  the  quantity  applied 

per  irrigation  cannot  be  less  than  3  acre-inches 
per  acre,  but  need  rarely  exceed  5  acre-inches. 

3.  The  number  of  irrigations  during  the  season  will 

depend  upon  the  crop  grown,  the  locality, 
the  soil  conditions,  the  rainfall — with  some 
crops — and  to  a  considerable  extent  will  de- 
pend upon  local  irrigation  customs  and 
practices. 

4.  Using  the  average  number  of  irrigations  and 

assuming  5  acre-inches  per  acre  per  irrigation 
for  alfalfa,  and  4  acre-inches  per  acre  for  all 
other  crops,  we  may  prepare  the  following 
table  to  show  the  probable  duty  of  water  for 
various  crops,  grown  under  average  climatic 
and  soil  conditions  with  pumped  water. 

The  following  quantities  are  to  be  regarded  as  ample  only 
where  the  greatest  care  is  taken  to  prevent  losses  in  dis- 
tribution and  where  the  most  advanced  ideas  in  cultivation 
and  soil  treatment  are  adopted  and  put  into  practice  to 
prevent  unnecessary  losses  by  evaporation  and  seepage. 


10 


PRACTICAL   IRRIGATION  AND   PUMPING 


On  very  gravelly  soils  newly  put  in  cultivation  double  the 
quantities  below  given  might  scarcely  suffice 

TABLE   III 
PROBABLE  DUTY  OF  PUMPED  WATER 


Crop 

Alfalfa 
per 
Cutting 

Small 
Grains 
Season 

Corn 
Season 

Sorghum 
Kaffir 
Corn 
Season 

Orchard 
Small 
Fruits 
Season 

Melons 
Season 

Truck 
Garden 
Season 

Acre-inches 

per  acre  . 

10 

12 

20 

26 

12 

24 

24-30 

Dry  Farming  Methods  an  Aid  to  Irrigation. — We  cannot 
too  strongly  emphasize  the  fact  and  shall  refer  to  it  from 
time  to  time,  that  financially  successful  irrigation  farming 
with  pumped  water  is  only  possible  when  the  idea  is  thor- 
oughly ground  home  that  pumped  water  is  expensive  and 
the  same  methods  and  practices  cannot  be  allowed  in 
irrigation  with  pumped  water,  as  prevail  on  farms  supplied 
from  gravity  canals.  Only  by  adopting  and  following  the 
best  practices  of  dry  farmers  in  the  conservation  of  soil 
moisture,  will  the  farm  ledger  show  a  satisfactory  profit 
when  pumped  water  is  used  for  irrigation.  This  is  true  un- 
der any  circumstances,  but  applies  with  special  force  to 
those  cases  where  the  total  lift  of  pumped  water  equals  or 
exceeds  50  feet. 

For  orchard  fruits,  of  course,  or  special  crops  such  as 
melons,  it  is  profitable  to  use  water  pumped  from  any 
reasonable  depth,  but  considerable  exercise  of  good  judg- 
ment and  first-class  business  management  are  necessary 
to  wring  a  profit  out  of  a  pumping  plant  under  other 
conditions. 


CHAPTER  II 

SOURCES   OF   SUPPLY 

Legal  Considerations  Surrounding  Use  of  Surface 
Sources. — Careful  investigation  should  be  made  of  the 
proposed  source  of  supply,  to  determine  its  adequacy  for 
the  proposed  scheme  and  the  nature  of  any  legal  or  physical 
difficulties  likely  to  be  encountered,  before  any  serious  con- 
sideration is  given  to  the  construction  or  economic  details 
of  a  pumping  project.  In  those  instances  where  it  is  pro- 
posed to  pump  water  from  a  flowing  stream  or  an  existing 
canal,  the  legal  right  to  the  use  of  the  water  should  first 
be  looked  into.  If  the  source  proposed  be  a  natural  flowing 
stream  or  river,  much  care  and  attention  should  be  paid 
to  securing  this  lawful  right  to  the  use  of  water,  if  the  proj- 
ect lies  in  any  of  the  states  where  water  laws  other  than 
the  doctrine  of  riparian  rights  exist  and  are  enforced. 
Where  the  old  common-law  doctrine  of  riparian  rights  exists 
it  is  doubtful  if  any  scheme  having  in  view  the  abstraction 
of  water  from  a  flowing  stream  and  its  use  in  the  irrigation 
of  adjacent  land  would  be  regarded  by  the  courts  as  lawful. 

In  the  arid  states,  on  the  other  hand,  where  the  right 
to  appropriate  and  use  the  water  of  flowing  streams  and 
other  natural  sources  is  recognized,  the  procedure  usually 
consists  in  making  application  to  the  State  Engineer  (in 
certain  prescribed  ways)  for  the  right  to  appropriate  a 
definite  quantity  of  water,  at  a  definite  point,  for  a  desig- 
nated purpose.  If  the  proposed  scheme  does  not  conflict 
with  other  rights  on  the  same  stream,  the  application  will 
be  granted  under  certain  conditions  as  to  diligence  in  con- 
struction of  the  necessary  works  and  bona-fide  use  of  the 

ii 


12  PRACTICAL   IRRIGATION   AND   PUMPING 

water  so  obtained  in  beneficial  ways.  In  those  instances 
where  it  is  proposed  to  pump  water  from  an  existing  canal 
or  reservoir,  a  contract  may  be  arranged  with  the  owners 
of  the  same  for  the  right  either  to  a  continuous  flow  of  a 
definite  number  of  cubic  feet  per  second  or  a  certain  num- 
ber of  acre-feet  during  a  season.  In  the  latter  case  certain 
stipulations  should  be  made  as  to  the  periods  in  which 
may  be  secured  the  fractional  amounts  making  up  the 
total  quantities  for  the  season. 

It  is  suggested  that  a  contract  calling  for  a  certain 
number  of  acre-feet  during  the  season  is  likely  to  be  the 
more  satisfactory  to  the  operator  of  the  pumping  plant, 
since,  unless  a  reservoir  is  provided  in  connection  with  the 
plant,  it  will  be  greatly  to  the  advantage  of  the  pumping- 
plant  operator  to  secure  relatively  large  flows  for  several 
short  periods  during  the  season,  than  a  small  continuous 
flow  throughout  the  season,  although  the  aggregate  amount 
in  acre-feet  will  be  the  same.  Such  a  contract  is,  however, 
difficult  to  secure  in  most  cases,  and  might  better  be  avoided 
altogether  unless  some  accurate  and  reliable  means  of 
measurement  be  provided  which  will  be  respected  by  both 
parties  to  the  contract. 

Adequacy  of  Supply — Surface  Sources. — In  general,  no 
extensive  study  need  be  made  of  the  question  of  adequacy 
of  supply  in  the  above  cases,  since  the  most  casual  inquiry 
(except  where  large  areas  are  involved)  will  satisfy  the 
engineer  or  prospective  owner  as  to  whether  there  is  likely 
to  be  a  sufficient  water  supply  for  the  purposes  contem- 
plated. Of  course,  if  the  project  involves  the  use  of  waters 
of  a  torrential  stream  flowing  only  in  times  of  excessive 
rainfall,  the  case  is  one  deserving  careful  study  of  all  avail- 
able information  as  to  rainfall  (yearly  normal,  maximum, 
minimum  and  periods  of  fluctuation,  rate  in  heavy  storms, 
run-off,  etc.),  and  as  to  the  physical  possibilities  and  cost 


SOURCES   OF   SUPPLY  13 

of  storage  works  or  reservoirs.  It  may  occasionally  be 
found  practicable,  in  unusually  favorable  locations,  to  store 
flood  waters  cheaply  and  pump  from  the  storage  basin  or 
reservoir  onto  adjacent  lands,  when  for  any  reason  a 
gravity  distribution  is  impossible.  Such  an  undertaking, 
if  of  any  extent,  needs  careful  study  from  the  stand- 
point of  cost,  since,  if  to  the  cost  of  a  pumping  plant  be 
added  that  of  storage  works,  the  land  must  be  fertile  and 
the  crops  profitable  to  pay  a  reasonable  return  on  the  in- 
vestment. 

Legal  Considerations — Underground  Sources. — The  le- 
gal side  of  the  other  method  of  securing  a  supply,  namely, 
by  pumping  from  wells,  is  not  as  important  as  when 
water  is  obtained  from  surface  sources;  the  only  apparent 
legal  necessity  at  present  is:  to  be  in  lawful  possession  of 
the  land  upon  which  the  plant  is  constructed. 

Doubtless,  with  an  increase  in  the  number  of  plants  in 
any  given  section,  many  interesting  legal  questions  will 
arise,  since  there  is  no  doubt  whatever  but  that  every 
additional  pumping  plant  drawing  water  from  the  com- 
mon underflow,  impairs  the  capacity  of  every  other  plant 
within  a  circle  whose  radius  will  be  larger  as  the  capacity 
of  the  plant  is  increased.  This  point  is  illustrated  in  many 
sections  of  the  West,  both  with  flowing  or  artesian  and 
pumped  wells.  In  the  Pecos  valley  of  New  Mexico,  the 
number  of  wells  tapping  the  artesian  source  has  grown  so 
large  that  nearly  all  of  the  first  wells  sunk,  which  formerly 
spouted  water  many  feet  in  the  air,  have  ceased  to  flow  at 
all  and  pumps  are  necessary  at  present  to  bring  to  the 
surface,  water  which  now  may  stand  in  the  well  tubes  some 
distance  below  the  ground  level.* 


*  In  many  instances  the  well  casings  have  been  eaten  through  by 
corrosion  at  various  depths  below  the  ground  level,  with  the  result  that 


14  PRACTICAL   IRRIGATION  AND   PUMPING 

In  some  districts  of  California,  where  pumping  has  been 
carried  on  extensively  and  thousands  of  plants  are  in  oper- 
ation, the  level  from  which  water  must  be  pumped  has 
lowered  tremendously,  indicating,  in  the  absence  of  struc- 
tural defects  in  the  wells,  that  the  field  has  been  over- 
developed. In  justice  to  the  original  and  older  plants,  it  is 
evident  that  some  legal  restriction  should  have  been  placed 
upon  the  construction  of  others,  in  case  the  evident  failing 
and  overdevelopment  of  the  field  did  not  of  itself  deter 
further  exploitation. 

Adequacy  of  Underground  Supply. — The  location  of  an 
underground  supply  and  its  probable  adequacy  when  found 
are  both  matters  largely  of  guesswork  and  upon  which  no 
one  should  venture  to  give  an  unguarded  or  definite  opinion. 
There  is  no  subject  about  which  less  is  definitely  known  or 
in  which  the  rules  are  subject  to  more  exceptions.  Although 
a  geologist  perfectly  familiar  with  a  region  may  give  cer- 
tain opinions  as  to  the  probability  of  an  artesian  supply 
being  found  and  its  probable  depth,  unseen  faults  or  fissures 
in  the  underlying  strata  may  completely  upset  his  calcu- 
lations. On  the  other  hand,  there  are  many  successful 
artesian  wells  drilled  upon  the  advice  and  under  the  inspi- 
ration of  a  local  seer  or  some  expert  with  a  " divining  rod" 
which  may  puzzle  the  geologists  to  account  for  at  all.  To 
a  greater  extent  is  this  true  of  the  shallower  subsurface 
water  strata  which  do  not,  as  in  the  case  of  artesian  sup- 
plies, depend  necessarily  upon  conditions  determined  by 


much  water  now  fails  to  reach  the  surface  and  leaks  away  underground. 
This  not  only  impairs  the  capacity  of  the  entire  artesian  field,  but  is 
helping  to  cause  saturation  of  the  soil  and  subsoil,  which  has  made  the 
alkali  and  drainage  problem  in  this  district  a  most  urgent  one.  The 
gradual  failure  of  this  heretofore  abundant  artesian  field  may  therefore 
be  quite  as  much  due  to  structural  defects  in  the  old  wells  as  to  the 
presence  of  later  borings. 


SOURCES   OF   SUPPLY  15 

geologic  formations  covering  va^t  areas  of  country,  but 
rather  upon  conditions  more  local  in  their  nature  as  regards 
rainfall,  surface  drainage,  and  porosity  of  soil  and  sub- 
soil; conditions  which  may  vary  tremendously  in  a  single 
township.  Beginning  in  Colorado  and  extending  far  into 
Texas,  is  a  vast  extent  of  territory  which  as  recently  as  ten 
or  fifteen  years  ago  was  considered  to  be  practically  without 
water  supply  of  any  character  aside  from  the  seasonal 
rains.  Now  in  this  region  wells  are  becoming  more  numer- 
ous each  year  and  gradually  a  vast  country  is  being  trans- 
formed from  a  rather  dubious  cattle  range  (due  to  lack  of 
water)  into  a  country  suitable  for  the  habitation  of  man. 
One  who  visited  the  plains  of  eastern  New  Mexico  and  the 
Texas  Panhandle  as  recently  as  ten  years  ago  would 
scarcely  deem  it  possible  that  now  in  this  region,  serious, 
sober-minded  American  farmers  by  the  hundreds  should  be 
attempting  to  make  their  fortunes  by  mixed  farming,  util- 
izing water  pumped  from  an  apparently  inexhaustible 
underground  supply  for  their  domestic  and  stock  needs  and 
the  few  acres  of  crops.  Although  few  extensive  pumping 
plants  are  in  operation,  windmills  are  seen  on  every  hand 
and  water  is  encountered  at  such  depths  as  make  it  appear 
reasonable  to  expect  that  in  the  not-distant  future,  small 
farms  irrigated  by  water  pumped  by  power  supplied  from  a 
central  source  will  be  a  commercial  reality.  The  source  of 
this  particular  supply  is  not  well  determined.  The  general 
theory  accepted  and  advertised  by  real-estate  boomers  and 
others  interested  in  the  disposal  of  these  lands  or  in  their 
colonization,  is  that  there  is  a  vast  underground  river  flow- 
ing from  the  distant  Rocky  Mountains  of  Colorado  toward 
the  Gulf  of  Mexico  and  that  beneath  every  acre  of  this 
region  is  to  be  found  sufficient  water  for  its  irrigation.  Such 
a  theory  is  doubted  by  geologists  who  are  inclined  to  account 
for  the  widespread  existence  of  underground  water  in  this 


i6 


PRACTICAL   IRRIGATION  AND   PUMPING 


region  upon  either  a  slowly  moving  underflow  in  connection 
with  some  adjacent  surface  stream  or  as  being  a  natural 
underground  reservoir  filled  in  past  ages  and  the  level  of 
which  may  be  lowered  more  or  less  rapidly  according  as 
the  amount  withdrawn  by  pumps  and  natural  outflow  ex- 
ceeds or  is  less  than  the  amount  reaching  the  underground 
reservoir  by  downward  seepage  of  the  natural  rainfall. 

Geology  of  Deep  Wells. — A  cross  section  of  a  valley 
which  may  be  regarded  as  typical  of  many  western  valleys, 
having  both  artesian  and  shallow  underground  supplies,  is 


Pervioua 
Stratum 

Impervious  Strata 
FIG.  2. — A  cross  section  typical  of  many  valleys  in  the  West. 

given  in  Fig.  2.  It  will  be  noted  that  the  source  of  the 
artesian  flow  lies  in  outcroppings  of  the  pervious  rock 
stratum  in  adjacent  mountains  and  this  water,  percolating 
slowly  through  the  porous  stratum,  will  rise  to  the  surface 
and  perhaps  give  considerable  pressure  at  the  outlet  of  a 
pipe  driven  from  the  valley  floor  deep  into  the  porous 
stratum  of  rock,  giving  a  flowing  or  artesian  well  at  point  A. 
Other  similar  wells  at  B  and  C  will  give  less  flow  or  may 
indeed  not  be  flowing  wells  at  all  and  must  be  operated 
with  pumps,  because  the  outlet  of  such  wells  lies  near  the 
hydraulic  gradient.  Eventually,  if  a  large  number  of  wells 


SOURCES   OF   SUPPLY  17 

are  sunk  into  the  porous  stratum  the  natural  flow  from  the 
first  wells  sunk  will  decrease  or  may  cease  altogether,  due  to 
the  lowering  of  the  hydraulic  gradient.  Eventually,  if 
pumping  is  resorted  to,  in  a  large  number  of  such  wells  the 
demand  is  likely  to  exceed  the  capacity  of  the  porous 
stratum,  the  depth  from  which  water  must  be  pumped  will 
become  excessive,  and  pumping  will  no  longer  be  profitable. 
The  capacity  of  the  artesian  field  is  determined  by  the  areas 
exposed  at  K — K  through  which  the  rain-water  may  per- 
colate, the  degree  of  porosity  of  the  water-bearing  stratum, 
and  the  degree  of  water-tightness  of  the  upper  and  nether 
strata.  A  pervious  stratum  of  relatively  high  density  will 
allow  of  but  very  slow  percolation,  due  to  fluid  resistance, 
so  that  though  considerable  pressure  may  be  developed  at 
the  surface  level  of  a  plugged  boring,  the  amount  of  water 
yielded  by  the  well  upon  removal  of  the  plug  will  be  very 
meagre.  The  artesian-well  question  is  largely  one  of  geology 
and  the  favorable  opinion  of  a  geologist  familiar  with  a 
region  should  be  obtained  before  wells  are  sunk,  for  although 
local  and  unforeseen  conditions  may,  as  they  have  in 
the  past,  entirely  invalidate  a  geologist's  conclusion  and 
judgment,  yet  it  is  only  where  a  hydraulic  condition  exists 
similar  to  that  represented  by  the  figure  that  artesian  wells 
are  possible,  and  before  putting  money  into  a  hole  like  an 
artesian  boring  it  is  advisable  at  least  to  know  whether  the 
probabilities  are  for  or  against  the  success  of  the  venture. 

Geology  of  Shallow  Wells. — In  a  valley  similar  to  Fig.  2 
there  may  be  a  second  body  of  ground  water  overlying  the 
first  and  occupying  the  porous  river  debris  deposited  in  the 
valley  trough  above  the  bed  rock  or  impervious  strata. 
This  debris  is  that  deposited  by  the  river  in  past  geologic 
ages,  and  may  consist  of  alternate  horizontal  layers  of 
gravel,  sand,  clay,  etc.,  with  occasional  pockets  of  sand  or 
gravel  deposited  by  the  ancient  river  in  the  same  way  as 


1 8  PRACTICAL   IRRIGATION   AND   PUMPING 

gravel  beds  and  sand  shoals  are  now  continually  being 
formed  by  our  modern  rivers.  This  ground  water,  as  it  is 
termed,  extends  across  the  valley  trough  at  a  surface  level 
corresponding  usually  to  the  mean  stage  of  the  water  in  the 
river,  though  the  level  at  which  ground  water  may  be  found 
is  often  greatly  affected  by  local  conditions  such  as  the 
presence  of  large  canals  on  near-by  benches,  the  seepage 
from  which  may  cause  local  elevations  of  the  ground-water 
plane  much  above  the  mean  level  of  near-by  watercourses 
or  drainage  channels.  Under  normal  conditions  the  ground 
water  will  have  a  surface  slope  in  the  direction  of  the  axis  of 
the  valley  which  will  be  approximately  the  same  as  the 
surface  slope  of  the  river  and  there  will  be  a  progressive 
movement  of  the  ground  water  downstream,  but  at  a  very 
slow  rate,  due  to  the  resistance  of  the  materials  through 
which  it  passes.  In  case  of  a  rocky  ledge  or  impervious 
barrier  across  the  valley  at  any  point,  a  large  underground 
reservoir  will  be  formed  above  this  point  and  after  a  long- 
continued  drouth,  when  the  surface  stream  may  have 
entirely  disappeared,  ground  water  will  be  found  at  approxi- 
mately the  level  of  the  lowest  crest  of  the  barrier.  Where 
there  is  no  barrier,  the  ground  water  will  continue  to  flow 
long  after  the  surface  stream  is  dry  and  there  will  be  a 
progressive  lowering  of  level  of  ground  water  due  to  this 
flow  as  long  as  the  drouth  continues  independently  of  any 
draught  upon  the  underflow  by  pumping. 

Many  streams  in  the  West  are  torrential  and  may  be 
very  large  rivers  immediately  after  heavy  rains.  During 
the  time  of  flow  of  the  surface  stream  a  large  amount  of 
water  percolates  downwards  and  to  a  less  degree  laterally 
into  the  sandy  bed  and  banks  of  the  stream,  and  continues 
its  downward  course  until  it  reaches  an  impervious  stratum, 
joins  existing  ground  water,  or  fills  the  interstitial  spaces  in 
the  porous  material  of  the  valley  trough.  Where  large 


SOURCES   OF   SUPPLY  19 

amounts  percolate  downward,  as  in  sandy  stream  beds 
during  long-continued  floods,  the  valley  bed  becomes  sat- 
urated for  great  distances  from  the  river,  and  subsequent 
to  the  passage  of  the  flood  there  will  be  a  subterranean  flow 
continuing  for  long  periods  and  giving  rise  to  what  are 
truly  called  "underground  rivers."  Again,  streams  may 
debouch  from  the  mountains  onto  a  sandy  plain  across 
which  it  may  flow  in  times  of  freshets  in  a  well-defined 
stream  bed,  but  at  other  times  the  stream  simply  disappears 
completely  into  the  sands  a  short  distance  from  the  point  of 
debouchure  onto  the  plain  and  continues  its  onward  move- 
ment very  much  more  slowly  as  an  underflow,  thus  giving 
rise  to  such  conditions  as  are  found  in  the  Mimbres  Valley 
of  New  Mexico,  where  underground  water  is  plentiful, 
although  the  Mimbres  River,  during  the  greater  part  of  the 
year,  is  represented  merely  by  a  broad  strip  of  white  sand 
winding  across  the  plain. 

Other  conditions  in  which  we  may  find  ground  water 
are  best  represented  by  a  great  saucer-like  basin  filled  with 
pervious  materials  which  absorb  the  greater  part  of  the 
yearly  rainfall,  and  in  which  the  ground-water  level  will  rise 
eventually  to  the  lowest  point  in  the  rim  of  the  basin.  Such 
basins  usually  have  a  surface  topography  so  flat  as  to  be 
devoid  of  extensive  or  important  surface  streams,  the  run- 
off during  periods  of  heavy  rainfall  merely  running  into 
depressions  where  it  remains  until  absorbed  by  the  soil  or 
is  evaporated.  In  localities  in  which  such  conditions  exist 
water  may  be  encountered  at  shallow  depths,  but  it  is  likely 
to  be  alkaline,  due  to  the  leaching  out  of  soluble  salts  in 
the  surface  layers  by  the  passage  of  rain-water  into  the 
ground  water  and  the  gradual  concentration  of  these  salts 
due  to  lack  of  drainage.  Many  such  basins  are  known  in 
the  Southwest,  of  which  the  most  notable  is  the  great 
Estancia  Valley. 


CHAPTER  III 


THE   FLOW   OF   UNDERGROUND   WATER 

Rate  of  Flow. — In  the  preliminary  investigations  which 
should  precede  any  underflow  pumping  project  of  impor- 
tance, an  inquiry  into  the  adequacy  of  the  supply  and  the 
determination  of  the  size  and  number  of  the  borings,  or  a 
decision  as  to  the  character  of  the  works  by  which  the 
supply  shall  be  developed,  must  necessarily  take  place  first. 
Such  an  inquiry  must  be  based  first  of  all  upon  some  knowl- 
edge or  information  as  to  the  rate  at  which  water  will  percolate 
through  the  water-bearing  materials  to  the  gathering  works. 

The  rate  of  flow  of  the  ground  water  is  a  matter  upon 
which  there  has  been  much  speculation  and  investigation, 
and  although  the  factors  governing  the  phenomenon  are 
too  numerous  and  too  indefinite  to  make  possible  a  satis- 
factory prediction  for  a  local  case,  at  least  two  conditions 
are  known  to  have  a  very  important  effect  in  determining 
the  rate  of  flow,  namely,  the  surface  slope  of  the  under- 
ground stream  and  the  porosity  of  the  materials  in  which 
the  flow  occurs. 

Turneaure  gives  the  following  table  as  being  applicable 
to  the  determination  of  rate  of  flow  of  underground  water. 

TABLE  IV 
RATE  OF  FLOW  IN  FEET  PER  DAY 


Material 

Slope  of  Water  Surface  Ft.  per  Mile 

IO 

20 

30 

40 

50 

IOO 

Fine  sand  

O.2 

0.4 

0.6 

0.8 

I.O 

2.O 

Medium  sand  

i-5 

3-0 

4-5 

6.0 

7-5 

15.0 

Coarse  sand 

40 

8  o 

12    O 

16  o 

20  o 

4.O  O 

Fine    gravel    free 

from  sand  

20-40 

40-80 

60-120 

80-160 

I  00-200 

200-4OO 

20 


THE  FLOW  OF  UNDERGROUND  WATER         21 

If  the  width  of  the  underground  stream  and  the  average 
depth  to  the  underlying  impervious  stratum  can  be  deter- 
mined, and  if  the  slope  of  the  ground-water  surface  be  meas- 
ured, by  the  relative  elevation  of  water  standing  in  wells 
sunk  some  known  distance  apart  along  the  axis  of  flow, 
some  idea  of  the  amount  of  water  passing  in  the  under- 
ground stream  may  be  gained  by  use  of  the  above  table, 
using  as  arguments  slope  and  character  of  water-bearing 
materials.  Unfortunately,  it  is  seldom  possible  to  ascertain, 
even  approximately,  the  vertical  and  lateral  limits  of  an 
underground  stream  and  such  calculations  are  apt,  there- 
fore, to  be  of  little  real  value. 

The  Ground-Water  Surface. — When,  as  is  shown  in 
Fig.  2,  a  number  of  wells  are  sunk  into  the  shallow  under- 
ground supply,  there  will  be  during  pumping  a  local  lower- 
ing of  the  surface  of  the  underground  water  which  in  the 
absence  of  pumping  is  a  plane  surface,  which  transversely 
to  the  axis  of  the  river  extends  horizontally  at  about  the 
level  of  its  mean  stage  and  which  in  a  direction  parallel  to 
the  river  takes  its  mean  slope. 

In  the  case  of  an  underground  reservoir  the  surface  of  the 
ground  water  will  of  course  be  level  in  all  directions  except 
during  pumping.  While  pumping  is  going  on,  however,  the 
surface  will  be  relieved  by  a  series  of  approximately  cup- 
like  depressions,  at  the  centre  of  each  of  which  will  be  a  well 
from  which  water  is  being  pumped.  A  vertical  section 
through  the  centre  of  one  of  these  depressions  will  show  the 
intersections  with  the  water  surface  as  a  pair  of  curved 
lines,  hyperbolas  A  B,  C  D — Fig.  3,  which  gradually  ap- 
proach the  ground-water  plane  as  they  recede  from  the  welL 

Revolving  one  of  these  curves  through  a  circle  will 
sweep  out  a  volume  of  which  a  section  is  G-A-B-C-D-F. 
While  pumping  is  in  progress,  this  volume  will  contain 
material  from  which  water  has  been  drained,  and  below 


22 


PRACTICAL   IRRIGATION   AND   PUMPING 


this  volume  the  water-bearing  materials  will  be  saturated 
and  a  flow  of  water  will  be  occurring  from  every  direction 
into  the  well  tube.  The  rate  at  which  water  flows  through 


MM 


Level 


of 


Material 
E      Standing        Water 


Water    Bearing 


Water 

Bearing 

Material 

Saturated 


Bearing 
Material 
Saturated 


FIG.  3. — Illustrating   condition   of   water-bearing    materials   surrounding   well    tube, 
during  pumping. 

the  water-bearing  materials  towards  the  well  tube  will  be 
a  measure  of  the  capacity  of  the  well.  This  rate  depends 
upon  two  conditions,  namely,  the  extent  to  which  the  water 
level  has  been  lowered  next  the  well  tube  or  the  distance 
C  E  and  upon  the  porosity  of  the  material. 


THE  FLOW  OF  UNDERGROUND  WATER        23 

"  The  Draw-down." — The  amount  of  lowering  C  E  or 
the  draw-down,  as  it  is  called,  determines  for  a  given  area 
of  strainer  opening,  the  amount  of  water  which  the  well 
will  yield  for  a  given  porosity  of  materials.  Thus,  with  the 
porosity  constant,  if  the  draw-down  is  increased  the  amount 
discharged  will  be  increased,  and  vice  versa.  Again,  if  we 
have  two  wells,  each  having  the  same  size  of  strainer  area 
and  yielding  the  same  amount  of  water,  the  one  located  in 
a  porous  bed  of  water-bearing  materials  will  have  less  draw- 
down than  one  in  dense  materials. 

The  amount  of  water  which  may  reach  the  well  depends 
upon  the  velocity  of  water  through  the  water-bearing 
material,  but  the  laws  and  constants  governing  this  velocity 
are  not  well  determined. 

Theory  of  Flow  into  Driven  Wells. — Some  investigations 
into  the  theory  of  flow  into  driven  wells  reveal  several 
considerations  of  interest  and  importance  in  a  practical 
way,  and  it  may  be  profitable,  therefore,  to  consider  the 
case  where  a  well  is  sunk  into  a  water-bearing  stratum  re- 
mote from  interference  by  other  wells  and  in  which  there  is 
no  general  horizontal  flow  of  the  ground-water,  i.e.,  its 
surface  is  level. 

Let  C  D  E  F,  Fig.  4,  be  a  pit  sunk  to  the  level  of  standing 
water  A  B,  and  let  G  represent  a  suction  tube  driven  into 
the  water-bearing  stratum  and  then  withdrawn  to  expose  a 
strainer  K  M.  With  such  an  arrangement  it  is  evident  that 
the  water  may  not  be  drawn  down  below  K  and  the  maxi- 
mum "draw-down"  will  be  L.  The  total  depth  of  the 
stratum  from  which  the  supply  is  drawn  is  H.  Since  in 
general  the  lines  of  saturation  K  N  extend  steeply  upwards 
at  first  and  then  slope  away  gradually,  no  very  great  error 
is  introduced  by  assuming  that  the  area  through  which 
flow  occurs  has  a  depth  H  and  that  since  this  area  is  the 
product  of  H  and  the  circumference  of  a  circle  whose 


FIG.  4. 


THE  FLOW  OF  UNDERGROUND  WATER        25 

radius  is  r,  evidently  the  area  will  increase  directly  as  r. 
Hence,  if  Q  is  the  discharge  in  any  convenient  unit,  the 

Q 

velocity  V  at  any  radius  r  will  be    V  =     _  T-,-* 

It  has  been  shown  by  various  experimenters  that,  for  a 
given  character  of  material,  the  flow  of  water  through  such 
material  is  a  function  of  the  surface  slope,  and  the  porosity. 

At  a  radius  r  from  the  well  tube,  let  the  slope  be  -r-  then 
V  =  K  j—  where  K  =  the  porosity  coefficient  and  from  the 

Trdh 
above  K    —  = 


d  r     27rrH 
From  this  we  find  by  integration: 


Where  H  1  =  length  of  strainer 

d  =  diameter  of  strainer 
H  =  distance  of  bottom  of  strainer  below  the 

level  of  standing  water 
K  =  a  constant  depending  upon  the  material. 

According  to  Lembke  the  values  of  this  constant  are  as 
follows : 

*See  Turneaure  and  Russell's  "Public  Water  Supplies  "  (Wiley  & 
Sons)  for  a  formula  based  on  the  theoretically  correct  assumption  that 
the  annular  space  through  which  water  flows  is  governed  by  the  vertical 
distance  from  a  plane  M  to  the  saturation  line.  Such  an  assump- 
tion is  avoided  in  the  present  discussion,  since  it  leads  to  an  equation 
extremely  difficult  to  integrate. 


26  PRACTICAL  IRRIGATION  AND   PUMPING 

Material.  K. 

Sand  and  gravel 9,400 

Coarse  sand 2,800 

Medium  sand 760 

Fine  sand 150 

This  equation  is  approximately  that  of  the  curve  of  satura- 
tion and  for  given  values  of  Q,  H,  and  K  the  value  of  h  —  H1 
may  be  determined  for  various  values  of  r,  thus  enabling 
the  saturation  curve  to  be  plotted  as  roughly  shown  in  Fig.  3. 
By  this  equation  but  little  of  practical  value  can  be  deter- 
mined with  regard  to  the  probable  yield  of  the  well,  since 
too  many  factors  are  involved.  The  yield  Q  is  the  quantity 
desired,  but  this  cannot  be  found  from  the  above  equation 
except  when  r  is  known,  and  this  is  usually  indeterminable. 

However,  it  is  possible  to  work  out  a  few  useful  relations 
based  upon  the  time  required  to  attain  a  certain  draw- 
down with  a  given  discharge,  which  will  help  to  clear  up  the 
question  of  how  deep  to  bore  a  well  and  what  draw-down 
will  be  necessary  to  secure  different  discharges. 

Referring  to  Fig.  3  we  see  that  a  solid  of  revolution 
G  F  D  C  B  A  (where  G,  A,  F,  and  D  are  located  at  points 
where  the  curve  of  saturation  practically  coincides  with 
the  water  plane)  represents  at  any  given  time  the  amount 
of  water  which  has  been  pumped  up  to  that  time.  This 
volume  may  be  determined  by  using  the  equation  just  de- 
termined and  integrating  for  volume.  In  Fig.  4  consider 
the  differential  volume  swept  through  in  one  revolution 
by  the  elementary  section  of  length  Z  and  width  d  r. 

Thus  we  have : 

dU=  2  TT  r  Z  dr 

But  Z  =  L  -  (h  -  H1);    hence  we  have: 

dU=27rLrdr-27rrdr  27rKH  loge  - 

d 
Let  —  =  unity  and  integrating  we  have : 


THE  FLOW  OF  UNDERGROUND  WATER 


27 


In  this  equation  r  is  taken  between  limits  of  R  and 

—  where  R  is  the  radius  of  the  circle  of  influence  when  h  is 
2 


27rKHL 


practically  equal  to  H  or  R  =  e      Q          Neglecting  values 
multiplied  by  —we  have: 


where  S  =  per  cent,  of  pore  spaces  in  the  water-bearing  ma- 
terial. 

The  Equation  for  Time  of  Pumping. — If  Q  =  volume 
drawn  continuously  through  the  well  tube  in  a  unit  of  time, 
we  have: 

T  =  ^r  where  T  will  be  in  same  units  of  time  as  Q. 

47TKHL-,        |-T  Q         -, 


Hence  :  T  =  =  -^ 


2.3  Q 


DIAGRAM  SHOWING  ADVANTAGE  OF  DEEP  BORING 

AND  LONG  STRAINER  IN  PROLONGING  PRODUCTIVE 

PERIOD  OF  WELL  AND  REDUCING  "DRAW-DOWN" 


40 

e 

iso 

I 

° 


10 


0     1     2     3     4     5     6     7     8     9    10    11    12    13  14   15   16   17  18  19   20 
Days  Pumping 

DIAGRAM  2 

Using  this  equation  we  may  compute  the  draw-down  L 
corresponding  to  different  lengths  of  time  of  pumping  with 


28  PRACTICAL  IRRIGATION  AND  PUMPING 

fixed  values  of  Q  and  soil  porosity,  and  using  different 
values  of  total  depth  of  well. 

In  Diagram  2  is  shown  a  series  of  curves  plotted  with 
draw-down  against  time  of  pumping  for  a  discharge  of 
1,000  g.p.m.  with  a  value  K  =  300,  a  percentage  of  po- 
rosity of  .30,  and  various  draw-downs  and  depths  of  well. 
A  series  of  values  for  the  same  quantities  are  given  in 
Table  IV  (a). 

In  this  table  is  seen  very  clearly  the  effect  of  sands  of 
different  degrees  of  fineness  upon  the  yield  of  the  well  and 
the  "  draw-down."  The  advantage  of  deep  wells  and 
long  strainers  in  fine  material  is  also  shown  by  this 
table.  It  is  to  be  understood  that  the  table  is  based 
upon  the  assumption  of  a  limitless  body  of  underground 
water  with  no  accessor^  supply. 

The  deductions  to  be  made  from  such  a  table  are  as 
follows : 

1 .  The  deeper  the  well  the  less  the  draw-down  for 

a  given  flow. 

2.  The  longer  the  strainer  the  greater  the  time  the 

well  will  give  the  required  flow  without  ex- 
ceeding the  desired  or  allowable  draw-down. 

3.  In  fine  material,  deep  wells  and  long  strainers 

are  essential. 

The  above  equation  may  also  be  used  to  determine 
approximately  the  flow  which  may  be  expected  under  a 
given  set  of  conditions.  Thus  let  it  be  assumed  that  it  is 
desired  to  know  what  flow  can  be  secured  from  a  well 
driven  30  feet  into  the  water-bearing  stratum  and  pro- 
vided with  a  lo-foot  strainer.  It  is  desired  that  it  be  pos- 
sible to  pump  continuously  during  six  months  without 
the  draw-down  exceeding  the  allowable  20  feet.  Also  the 
water-bearing  material  has  a  porosity  of  30  per  cent,  and 
an  effective  size  of  grain  of  .2  millimeters. 


THE  FLOW  OF  UNDERGROUND  WATER 


H 

w 

0 
CM 

i  ;'.!•*  |-  i.  '!."!  ;'•! 

1  = 

0) 

;       to       O        O          ;;;••• 

rH      [> 

i 

n 

oo        !        !        !        I        i        * 

w  2 

..  • 

H    9 

«r 

g  £ 

S 

0 

cd  o 

i 

;         t     :     :     !     i     !     :     : 

M     * 

°*a> 

<*H 

*  § 

| 

7- 

o 

:§:::::::: 

33| 

S 

1 

'     ^      '      '.      '.      '.      '.      '.      '.      '. 

d>  S 

UJ 

water 

g 

:    |   '•:•";':  .':.'-,!':'   I   •:: 

o  m   g 

I 

:§-:::::::: 

i-T  £>   £ 
a,  H   S 
,5 

>   j  ^ 

a 

! 

a 

!   i   i   1  ?  -  s  i   M 

W   |    H 

3     n    »    ^ 

-      H    Z    $ 

5i 

•s 

» 

;   !   !   !  ?  ^  »  !   j  i 

>    \  8  a 
~  g  g  B 

W    ^  §  < 

J  S  §2 

w  pp 

1 

a 

i  ;  i  i  ?  *  I  i  i  i 

W     ,  65 

^     W    P    en 
H^      09   C/5    & 
o 

3-^9 

53^ 

_3 

1 

1 

"o 

• 

:      :      :      :     «    5     |     :      :      : 

M 

y   K> 
J    ^    55 
*£  §    " 

„ 

1 

i 

0 

O           . 

^     B 

<m 

| 

<  5  5 

W     Q    ^ 

^    W    iJ 

1 

H 

0 

;   ;   :   ;   ;  f  |  5-  ^.  ; 

it3    . 

Q     y     W 

N 
gtn 

83 
g 

o 

;   !   !   [f  :*.??*1 

8J 

b 

0 

i  !  i  |..  t  -"••*.  a  f 

TABLE  SHOWI 
WATER 

Draw-down 

or  H*»nth  of 

lowering 

J 

----- 

PRACTICAL   IRRIGATION  AND   PUMPING 


TABLE   V* 
VALUES  OF  — 


EFFECTIVE  SIZE  OF  SAND  GRAINS  IN  MILLIMETERS 


Porosity 
per  cent. 

.10 

.20 

.30 

.40 

•50 

.80 

I.OO 

20 

22 

89 

2O2 

358 

56o 

1,430 

2,240 

25 

28 

112 

252 

448 

700 

1,790 

2,800 

30 

34 

134 

302 

537 

840 

2,150 

3,360 

35 

39 

157 

353 

627 

980 

2,570 

3,920 

T£ 

Using  Table  V  we  find  that  —  for  the  porosity  and 

2.o 

effective  size  of  sand  grains  is  134. 

The  involved  form  of  the  equation  makes  it  difficult  to 
determine  a  value  of  Q  for  a  given  value  of  T,  hence  it  is 
most  easy  to  assume  several  values  of  Q  and  for  the  values 
of  T  so  found  plot  a  curve  from  which  the  particular  Q  for 
the  desired  time  may  be  interpolated.  Such  a  curve  is 
shown  in  Diagram  3. 

It  will  be  noted  that  the  value  of  Q  for  180  days  is  about 
225  gallons  per  minute.  The  above  dimensions  and  size 
of  sand  and  porosity  were  chosen  for  an  example,  since  they 
correspond,  approximately,  to  the  conditions  existing  at  a 
12-inch  well  sunk  by  the  writer  to  a  depth  of  30  feet  below 
the  surface  of  ground  water  with  a  strainer  19  feet  long 
where  the  draw-down  rarely  exceeded  17  feet.  This  well 
yielded  by  actual  measurement  from  300  to  350  gallons  per 
minute,  a  sufficiently  close  check,  in  this  instance  at  least, 
to  warrant  some  faith  in  the  formula  and  constants.  A 
second  curve  for  a  lo-foot  greater  penetration  is  also 


*  Taken  from  Turneaure  and  Russell's  "Public  Water  Supplies." 


THE  FLOW  OF  UNDERGROUND  WATER 


31 


shown  in  Diagram  3,  from  which  it  appears  that,  for  condi- 
tions otherwise  the  same  as  before,  about  300  gallons 
per  minute  might  be  developed  for  the  same  limiting 
draw-down. 

Limitations  of  the  Formula. — At  best  it  must  be  con- 
ceded that  estimates  based  upon  such  a  formula  as  above 


20 


140          180          220 
Days  Pumping 


340 


DIAGRAM   3 

SHOWING  RELATION  BETWEEN  TIME  OF  PUMPING,  DISCHARGE 
AND  DEPTH  OF  WELL  FOR  GIVEN  DRAW-DOWN  AND  WATER-BEARING 
MATERIALS 

derived  are  but  little  more  than  approximations,  and  before 
the  formula  can  be  applied  it  is  necessary  to  make  a  care- 
ful investigation  of  the  water-bearing  sand  to  determine 
its  porosity  and  the  effective  size  of  grain.* 

With  this  information  at  hand  the  formula  may  be 

*  Porosity  of  the  water-bearing  material  may  be  determined  by 
placing  a  quantity  of  the  dry  material  in  a  vessel  of  known  volume, 
shaking  it  down  thoroughly  and  measuring  the  volume  of  water  neces- 
sary to  fill  the  voids,  i.e.,  the  amount  which  may  be  poured  into  the 


32  PRACTICAL  IRRIGATION  AND   PUMPING 

applied  as  above  illustrated  and  some  idea*  obtained  of  the 
depth  necessary  to  drill  the  well  and  the  length  of  strainer 
necessary  for  a  given  capacity.  It  must  be  understood, 
however,  that  the  formula  is  based  on  conditions  which 
rarely  exist,  i.e.,  an  underground  reservoir  of  indefinite 
extent  and  no  flow  occurring  other  than  that  due  to  the 
draught  from  the  well  in  question. 

The  more  usual  conditions  are  those  encountered  in 
river  valleys  where  a  slow  movement  of  water  occurs  in  the 
direction  of  the  river  slope  and  where  consequently  the 
surfaces  formed  by  the  lines  of  saturation  will  be  unsym- 
metrical  on  an  axis  parallel  to  the  stream,  being  steeper  on 
the  upstream  side,  while  a  flow  will  be  constantly  entering 
the  circle  of  influence  to  replace  water  already  pumped  out. 
In  such  case  the  formula  will  probably  give  slightly  smaller 
values  than  will  actually  be  realized  and  the  estimate  will 
therefore  be  on  the  conservative  side. 

Interference  of  Wells.  —  The  above  will  not  hold  good 
where  other  active  wells  are  within  the  circle  of  influence 
of  the  one  proposed.  Thus,  in  the  case  previously  cited, 
where  H  =  30,  L  =  20,  Q  =  300  G.P.M.  we  have 


R  =   10  -  pr—    =  626  ft. 
2-3  Q 


dry  material  before  water  flushes  to  the  surface.  The  ratio  of  this 
volume  to  the  total  volume  of  sand  is  the  porosity;  thus  in  a  sand  of 
20  per  cent,  porosity,  20  per  cent,  of  the  volume  consists  of  voids  be- 
tween the  particles. 

The  effective  size  of  grain  is  an  arbitrary  but  convenient  designation 
for  comparing  the  size  of  grain  in  various  grades  of  sand.  The  effective 
size  of  sand  grain  is  the  same  as  the  size  of  mesh  in  millimeter  of 
that  screen  which  will  allow  10  per  cent,  by  weight  of  a  sample 
of  the  dry  sand  to  pass  through  it,  but  will  retain  90  per  cent.  It  is 
much  less  than  the  average  size  of  grain  in  ordinary  sand.  The  deter- 
mination of  the  effective  size  requires  the  use  of  a  set  of  standard  milli- 
meter screens  and  an  accurate  balance  for  determining  the  respective 
weights. 


THE  FLOW  OF  UNDERGROUND  WATER        33 

where  R  is  radius  of  circle  of  influence  or  is  the  distance 
from  the  well  at  which  the  line  of  saturation  reaches  the 
level  of  the  normal  water  plane.  If  another  well  of  equal 
size  and  capacity  be  located  closer  than  1,250  feet  =  2  R 
the  lines  of  saturation  will  cross  and  the  wells  will  interfere, 
each  cutting  down  the  capacity  of  the  other.  The  effect 
of  a  number  of  wells  in  the  same  locality,  sunk  into  the 
same  water-bearing  stratum,  is  obviously  to  cause  a  decrease 
in  the  flow  of  each,  and  this  effect  will  be  the  more  marked 
as  the  distance  between  them  is  decreased.  Under  such 
circumstances  it  is  difficult,  if  not  impossible,  to  arrive  at 
any  satisfactory  estimate  of  the  quantity  of  water  a  well 
will  provide,  and  in  this  case,  as  indeed  it  may  be  said  of 
any  case,  the  only  way  to  determine  properly  and  with 
reasonable  certain  accuracy  the  capacity  of  a  well  is  first 
to  bore  the  well,  connect  it  to  a  pump  and  try  it,  noting  not 
only  the  quantity  of  water  obtained,  but  also  the  draw-down 
and  the  length  of  time  the  quantity  may  be  pumped  with- 
out seriously  increasing  the  draw-down. 

Practical  Limits  of  Draw-down. — So  far  in  this  discus- 
sion we  have  assumed  that  the  draw-down  or  lowering  of 
level  of  the  ground  water  in  the  vicinity  of  the  well  may 
not  exceed  the  feasible  suction  lift  of  20  feet.  The  draw- 
down may  be  made  greatly  to  exceed  this  limit  by  placing 
the  pump  itself  below  the  normal  water  plane.  Such  con- 
struction, however,  with  any  sort  of  pump  except  the  com- 
mon well  or  pump  cylinder,  a  vertical  turbine  pump,  or  an 
air-lift,  is  very  expensive  in  respect  to  the  construction  of 
the  well.  Moreover,  the  deep  well-pump  cylinder  has  too 
limited  a  capacity  for  the  irrigation  of  other  than  orchards 
or  truck  gardens;  the  turbine  pump  is  yet  very  high  in  price, 
and  the  air-lift  too  expensive  in  operation.  Consequently 
it  may  be  said  that  it  is  not  advisable  for  one  contemplating 
irrigation  on  a  more  or  less  extensive  scale  by  pumping,  to 


34 


PRACTICAL   IRRIGATION  AND   PUMPING 


have  a  greater  draw-down  than  the  usual  working  suction 
limit  of  20  feet,  except  where  orchards  are  to  be  grown. 

Size  of  Well  Tube. — In  the  formula  derived  on  page  25 
the  effect  of  the  size  of  the  well  tube  upon  the  discharge  was 
purposely  neglected.  It  may,  however,  be  shown  that 
with  other  conditions  the  same,  the  supply  is  only  slightly 
increased  by  a  large  increase  in  diameter  of  well  casing. 


#1 

22 

20 
18 

$16 

.E 

|14 
kl2 

£ 
•gio 
§ 

02    8 

6 
4 
2 

1 

DIAGRAM  SHOWING 
RELATIVE  CAPACITIES 
OF 
DRIVEN  WELLS 
OF 
VARIOUS  DIAMETERS 
PIPE  FRICTION 
DISREGARDED 

I 

/I 

/ 

/ 

I 

0.5  1.0  1.5 

Relative  Capacities 

DIAGRAM   4 


2.0 


This  is  illustrated  by  above  diagram,  in  which  the 
capacity  of  a  2-inch  well  tube  is  represented  by  unity  and 
that  from  other  sizes  under  the  same  set  of  conditions  by 
comparative  values  as  represented  by  the  curve.  It  will 
be  noted  that  an  increase  in  size  from  2  to  24  inches 
gives  only  40  per  cent,  increase.  As  the  water-bearing 
material  increases  in  density  the  comparative  increase  in 
capacity  is  still  less  for  the  large-sized  casings.  This  con- 


THE  FLOW  OF  UNDERGROUND  WATER         35 

elusion  is,  of  course,  independent  of  frictional  effects  in  the 
casing  itself,  and  losses  in  head  at  entrance,  but  it  confirms 
what  is  generally  conceded  in  practice,  namely,  that  the 
use  of  very  large  casing  for  shallow  tubular  wells  is  of  doubt- 
ful practicability.  The  experience  of  the  writer  leads  him 
to  believe  that  for  most  irrigation  pumping  work,  8-inch 
pipe  or  casing  is  the  largest  which  should  be  used  and  that 
not  smaller  than  3-inch  should  be  adopted  for  any  irrigation 
work,  however  small  the  plant.  The  recommendation  in 
regard  to  8-inch  casing  is  made  in  view  of  the  fact  that  this 
size  is  about  as  heavy  as  can  be  handled  conveniently  by 
the  common-size  drilling  rig  and  the  friction  loss  for  the 
largest  amounts  of  water  which  can  be  developed  in  a 
single  well,  will  not  be  appreciable  in  the  length  of  casing 
required  for  a  well  of  that  depth  which  in  the  small  pump- 
ing plant  it  will  be  found  practicable  to  sink.  In  thus 
stating  what  he  regards  as  good  judgment,  the  writer  has 
in  mind  the  idea  of  a  small  plant  installed  by  an  indi- 
vidual or  community  for  irrigation  of  common  crops  or 
for  domestic  water  supply. 

Even  for  large  projects,  however,  common  experience  is 
decidedly  against  the  attempt  to  "corral"  a  large  supply 
by  one  large  expensive  boring.  It  is  far  better  to  sink  a 
large  number  of  small-sized  wells  to  a  considerable  depth 
than  one  large  one  to  the  same  depth,  both  from  the  stand- 
point of  expense  and  amount  of  water  yielded.  Indeed, 
the  large  irrigation  pumping  plant  in  its  most  feasible  and 
up-to-date  form  includes  a  large  number  of  small  wells 
scattered  over  the  area  to  be  irrigated,  each  well  pumped 
by  a  motor  operated  by  electric  power  transmitted  from  a 
central  power  station.  Such  a  scheme  is  much  more  flexible ,, 
cheaper  in  first  cost,  and  in  every  way  more  economical 
and  satisfactory  even  when  the  area  to  be  irrigated  is 
sufficiently  compact  and  small  in  extent  to  make  it  possible: 


36  PRACTICAL  IRRIGATION  AND  PUMPING 

to  distribute  water  over  it  from  one  central  point  at  which 
the  large  boring  might  be  located.  In  passing,  it  may  be 
said  that  experience  has  shown  that  one  thousand  gallons 
per  minute  is  about  the  largest  quantity  of  water  it  is 
feasible  to  pump  from  individual  driven  wells  for  irrigation 
purposes. 


CHAPTER  IV 

STRAINERS 

Definition. — Referring  again  to  Fig.  4,  we  see  that  the 
portion  of  the  pipe  K  M,  included  between  the  bottom  of 
the  boring  and  the  level  of  the  water  in  the  immediately 
surrounding  material  at  the  time  of  greatest  draw-down, 
should  be  an  area  through  which  water  may  pass  into  the 
well  pipe.  In  certain  kinds  of  material  this  might  be  simply 
an  unlined  hole,  but  in  the  great  majority  of  cases  this 
portion  of  the  well  must  be  a  perforated  portion  of  the 
casing  and  is  called  the  "strainer."  Evidently  its  only 
purpose  is  to  prevent  caving  in  of  the  surrounding  material 
into  the  well  tube.  The  strainer  obviously  should  in  no 
case  extend  above  the  lowest  point  of  draw-down,  since  in 
that  event  air  would  enter  the  well  tube  and  destroy  the 
vacuum  by  which  the  pump  is  enabled  to  cause  a  flow 
up  the  well  tube  in  case  the  pump  is  directly  connected  to 
the  upper  end  of  casing.  In  case  a  draught  tube  is  dropped 
down  inside  the  casing  the  vacuum  will,  of  course,  not  be 
destroyed  by  the  strainer  extending  above  the  lower  line 
of  draw-down,  but  the  portion  of  strainer  extending  above 
this  limit  is  useless.  For  this  reason,  and  because  the  suc- 
tion limit  is  about  25  feet,  even  at  low  altitudes,  the  top 
of  the  strainer  should  not  extend  above  that  depth  below 
the  normal  level  of  standing  water. 

Special  Cases  Governing  Depth  of  Strainer. — It  some- 
times happens  that  the  water-bearing  stratum  from  which 
it  is  feasible  to  obtain  water  does  not  extend  more  than 
25  feet  below  the  level  of  standing  water.  This  case  is 

37 


38  PRACTICAL  IRRIGATION  AND  PUMPING 

illustrated  in  the  following  figure  in  which  on  the  left  is 
shown  a  quicksand  or   fine-sand  stratum,  on  the  right  a 


FIG.  5. — Showing  use  of  suction  pipe  inside  of  casing  to  develop  shallow  water  stratum. 

clay  stratum  at  a  depth  of  about  25  feet  below  standing 
water  level,  and  in  either  case  the  boring  should  of  necessity 
not  extend  much  below  the  bottom  of  the  gravel  stratum. 


Water  Bearing 
Gravel 


I 


Clay 


Water  Bearing 
Sand  and  Gravel 


Fine  Sand 


Clay 


Gravel 


tanding  Water  Level 


Shale 


0  0.0    O  Q    "  0 


FIG.  6. 


4O  PRACTICAL  IRRIGATION  AND   PUMPING 

Here  a  strainer  10  or  12  feet  long  may  be  used  and  a  suction 
pipe  lowered  inside  of  the  casing  so  that  its  inlet  is  20  to 
25  feet  below  the  level -of  standing  water.  Evidently  by 
this  means  the  water  level  may  be  drawn  down  to  the  limit 
of  suction,  but  the  yield  from  such  a  well  will  be  less  than 
from  one  where  a  greater  length  of  strainer  is  exposed,  there 
being  a  restriction  in  area  and  greater  loss  in  head  at 
entrance. 

Frequently  by  drilling  to  greater  depths  other  favorable 
water-bearing  strata  will  be  encountered,  as  is  illustrated 
in  Fig.  6.  In  this  case,  which  is  taken  from  an  actual  well, 
the  first  porous  stratum  below  standing  water  was  too 
shallow  for  the  placing  of  a  strainer,  and  below  this  was 
encountered  a  lo-foot  stratum  of  clay.  Below  this,  how- 
ever, was  found  a  splendid  bed  of  gravel,  and  below  this 
successive  strata  of  clay  and  gravel,  as  shown.  In  this 
instance  the  underground  conditions  were  determined  by  a 
preliminary  boring,  after  which  an  8-inch  casing  was 
driven,  into  which  at  proper  distances  along  its  length  were 
screwed  strainers  of  perforated  pipe  so  located  as  to  inter- 
cept the  gravel  strata  as  shown.  A  boring  of  this  character 
is  specially  adapted  for  yielding  water  suitable  for  domestic 
or  city  supply,  owing  to  the  fact  that  surface  water  strata 
which  are  most  likely  to  be  contaminated  are  cased  off  and 
the  supply  drawn  from  the  deeper  and  probably  purer  strata. 

Kinds  of  Strainers. — The  strainer  itself  may  be  made 
in  a  number  of  ways.  Probably  the  more  common  strainer 
is  a  section  of  pipe  of  the  same  size  as  the  well  casing,  per- 
forated by  drilling  throughout  its  length  a  great  number  of 
small  holes.  The  strainer  thus  made  may  be  used  without 
further  preparation,  where  the  stratum  to  be  intersected 
is  of  comparatively  coarse  gravel  and  little  or  no  sand. 
Such  strainer  should,  however,  either  be  galvanized  after 
the  holes  are  drilled,  or  in  case  that  is  not  feasible,  be  well 


STRAINERS  41 

coated  with  good  asphaltum  paint.  Where  the  stratum  to 
be  intercepted  is  of  sand,  which  is  the  usual  condition,  it 
may  be  advisable  to  surround  the  perforated  pipe  with  wire 
gauze  of  copper,  brass,  or  galvanized  wire,  or,  as  in  the  case 
of  the  Lane  strainer,  it  may  be  wrapped  with  a  layer  of 
wire,  triangular  in  section,  with  the  apex  lying  inwards, 
adjoining  wires  being  separated  to  provide  a  continuous 
narrow  spiral  slit  for  the  passage  of  water.  Such  a  strainer 
is  screwed  into  the  length  of  casing  and  sunk  with  it. 
Strainers  with  fine-mesh  gauze  are  necessary  when  the 
purpose  is  to  exclude  sand,  as  must  be  done  when  using  a 
pump  with  valves. 

A  strainer  of  deserved  merit,  but  of  entirely  different 
character,  is  that  known  as  the  Porcher.  This  is  much 
used  in  the  Rio  Grande  Valley  of  New  Mexico  and  Texas. 
It  is  of  heavy  galvanized  iron  sheeting  perforated  with 
elongated  holes  and  formed  into  a  cylinder  of  such  size  that 
it  will  pass  easily  inside  of  the  well  casing  used.  In  the  best 
form  the  perforations  are  punched  and  the  tube  formed  and 
riveted  previous  to  galvanizing,  which  insures  a  strainer 
capable  of  resisting  corrosion  for  a  considerable  length  of 
time.  Since  this  strainer  cannot  be  screwed  into  the  length 
of  casing  and  sunk  with  it,  the  practice  is  first  to  sink  the 
casing  to  a  point  at  which  it  is  desired  the  bottom  of  the 
strainer  shall  be,  a  matter  to  be  decided  upon  by  previous 
exploration  or  from  a  knowledge  of  the  character  of  strata 
encountered  during  the  process  of  sinking  the  casing.  The 
casing  having  been  sunk  to  this  level,  the  strainer,  cut  to 
proper  length,  is  lowered  inside  of  it  until  its  lower  end 
reaches  the  desired  level.  The  casing  is  now  withdrawn 
with  jacks  and  the  entire  length  of  strainer  exposed,  less 
about  6  inches  at  the  top.  Obviously,  the  casing  must 
be  in  sections  of  such  length  that  when  pulled  far  enough 
to  expose  the  strainer,  a  joint  will  occur  at  or  near  the  level 


42  PRACTICAL   IRRIGATION  AND   PUMPING 

of  the  ground  or  the  bottom  of  the  open  pit  in  case  the  latter 
method  has  been  adopted.  The  difficulty  in  withdrawing 
a  casing  in  some  formations,  limits  the  use  of  this  strainer 
to  driven  wells  not  over  50  feet  in  length  of  casing.  The 
strainer  may  be  secured  in  almost  any  desired  length  up  to 
20  feet,  since  it  may  be  made  in  sections  riveted  together, 
but  such  a  strainer  opposes  so  little  resistance  to  the  pas- 
sage of  water  that  its  length  for  any  size  of  casing  probably 
need  not  exceed  15  feet.  The  slots  are  made  of  such  width 
as  will  exclude  the  smallest  gravel  encountered  and  the  length 
of  slots  is  usually  from  i  to  i  J4  inches,  while  the  widths  vary 
from  J/g"  to  J4",  /i6  inch  being  a  common  size. 

It  is  apparent  that  such  a  strainer  will  not  exclude  sand, 
and  in  the  cases  where  it  is  used,  the  practice  is,  upon  com- 
pletion of  the  well,  thoroughly  to  flush  out  the  sand  by 
continuous  pumping  for  a  number  of  days.  This  strainer 
obviously  cannot  be  used  with  any  pump  other  than  a  cen- 
trifugal. In  a  gravel-and-sand  stratum,  the  continuous 
pumping  has  the  effect  of  removing  the  sand  from  a  con- 
siderable distance  around  the  strainer,  and  results  in  a 
natural  screen  of  gravel  about  the  strainer  which  affords 
free  passage  for  water  and  results  in  much  greater  capacity 
from  the  well  after  some  years  of  use.  The  amount  of  sand 
thus  removed  is  amazing,  sometimes  amounting  to  many 
carloads,  and  unless  special  provision  is  made  for  taking 
care  of  it,  considerable  trouble  may  be  encountered  at  first 
in  the  clogging  of  the  pump,  valves,  etc.  The  Porcher 
strainer  is  recommended  for  wells  in  cases  where  the  depth 
of  the  bottom  of  the  strainer  will  not  exceed  50  feet  below 
standing  water  level  and  where  the  water-bearing  forma- 
tion contains  50  per  cent,  by  volume  of  gravel  greater  than 
l/i"  in  greatest  dimension.  Where  the  proportion  of 
gravel  is  less  than  this  amount,  a  finer  strainer  may  have 
to  be  used,  but  the  writer  has  seen  the  Porcher  strainer 


STRAINERS 


43 


used  in  a  formation  decidedly  " quicksand''  in  character, 
by  pouring  in  around  the  top  of  the  strainer,  as  soon  as 
pumping  began,  a  large  quantity  of  screened  gravel,  which 
by  reason  of  its  weight  took  the  place  of  the  sand  as  it 
was  pumped  from  around  the  strainer  and  resulted,  even- 
tually, as  gravel  continued  to  be  added,  in  the  formation 
of  a  gravel  screen  around  the  strainer,  thus  enabling  water 
to  be  pumped  comparatively  free  from  sand. 

Cook  Strainer. — A  type  of  strainer  of  great  merit  is 
that  called  the  Cook  strainer,  illus- 
trated in  Fig.  7.  This  is  constructed 
of  brass,  with  slots  of  width  adapted 
to  exclude  all  but  the  smallest  size  of 
water-bearing  material.  These  slots 
are  wider  on  the  inner  than  the  outer 
periphery  of  the  tube,  thus  insuring 
against  mechanical  clogging  of  the 
openings.  In  certain  strongly  alka- 
line water  these  strainers  have  some- 
times been  clogged  by  deposition  of 
insoluble  alkaline  matter  due  to  chemi- 
cal reactions  induced  by  the  action  of 
certain  ingredients  in  the  water.  Be- 
fore using  such  a  strainer,  therefore, 
it  would  be  well  to  ascertain,  by  chemi- 
cal examination  of  the  water,  if  such 
action  is  apt  to  occur.  In  normal 
waters,  of  course,  the  brass  strainer 
will  greatly  outlast  an  iron  or  even 
galvanized-iron  strainer. 

Conclusions  on  Strainers. — In  conclusion,  with  regard  to 
strainers  it  may  be  said  that: 

i.   Strainers  over  20  feet  in  length  are  not  considered 
necessary  to  develop,  in  ordinary  water-bearing  sands  and 


FIG.  7. 


44  PRACTICAL  IRRIGATION  AND  PUMPING 

gravels,  the  quantity  of  water  which  may  be  secured  with 
usual  draw-down  of  15  to  25  feet. 

2.  Open  strainers  may  be  used  as  successfully  as  fine 
strainers  in  gravel  and  fine  sand  mixed  in  about  equal  pro- 
portions by  volume,  if  centrifugal  pumps  are  used  and  pro- 
vision is  made  for  taking  care  of  the  large  quantity  of  sand 
which  will  be  pumped  during  the  first  year  or  more  of 
operation. 

3.  Open  strainers  may  be  used  in  water-bearing  forma- 
tions with  large  proportion  of  very  fine  sand  if  gravel  is 
poured  in  around  the  strainer  as  pumping  progresses. 

4.  Drive  points  and  gauze  strainers  should  never  be 
used  except  with  small  capacity  piston  or  plunger  pumps 
from  which  sand  must  be  excluded. 


CHAPTER  V 

WELL   SINKING 

Practical  Suggestions. — It  will  not  be  within  the  scope 
of  this  work  to  give  more  than  a  few  brief  suggestions  to 
those  contemplating  the  construction  of  pumping  plants, 
and  who  are  not  familiar  with  the  problem  of  well  sinking, 
since  this  is  an  art  itself,  and  one  which  demands  the  exer- 
cise of  great  skill,  good  judgment,  and  considerable  experi- 
ence to  be  carried  on  successfully.  To  any  one  not  experi- 
enced in  the  matter,  the  writer's  advice  would  be  to  obtain 
the  services  of  a  competent  well  driller  with  a  good  outfit, 
when  any  well  larger  than  3  inches  in  diameter  and  over 
30  or  40  feet  deep  is  to  be  driven.  Wells  of  less  diameter 
and  less  depth  may  be  driven  by  a  resourceful,  patient 
man  not  provided  with  the  proper  well-drilling  equipment, 
but  for  larger,  deeper  wells  the  work  is  nearly  impossible 
without  proper  power  machinery. 

Well-Drilling  Machinery. — The  type  of  machinery  to 
employ  will  be  determined,  to  a  large  extent,  by  the  character 
of  materials  through  which  the  well  is  to  be  driven,  the  size 
of  the  casing,  and  the  contemplated  depth.  The  following 
classification  indicates  what  is  usually  considered  good 
practice  in  selection  of  machinery. 

SPUDDING  MACHINES. — These  machines  are  those  most 
generally  employed,  since  they  may  be  used  in  a  greater 
variety  of  materials  and  to  almost  any  depth  of  boring  or 
size  of  casing.  They  are  made  in  a  variety  of  sizes  by  a 
number  of  well-known  firms,  among  which  may  be  men- 
tioned the  American  Well  Works,  Aurora,  111.;  the  Key- 

45 


WELL   SINKING  47 

stone  Driller  Co.,  Beaver  Falls.,  Pa.;  Williams  Brothers, 
Ithaca,  N.  Y. 

A  large  steam-driven,  self-propelling  machine  made  by 
the  Keystone  Driller  Company  is  illustrated  in  Fig.  8. 

This  machine  has  capacity  to  drive  6-inch  wells  to  a 
total  depth  of  350  feet,  and  is  listed  at  about  $1,600  with 
complete  equipment  F.O.B.  factory. 

For  other  wells  a  variety  of  equipment  from  the  horse- 
driven  tripping  winch  to  the  more  costly  and  efficient 
machines,  will  be  found  listed  in  the  catalogues  of  the 
manufacturers  mentioned. 

JETTING  MACHINES. — These  machines  are  devised  to 
enable  more  rapid  drilling  in  soft  material  than  is  possible 
with  the  common  churn  drilling  or  spudding  machine. 
They  differ  but  little  from  the  latter  in  essential  particulars, 
the  jetting  machine  being  really  a  spudding  machine 
additionally  equipped  with  one  or  more  force  pumps  for 
sending  a  stream  of  water  down  the  boring  to  the  point  of 
the  drill.  An  illustration  of  a  small,  easily  portable  machine 
of  this  type  shown  adapted  to  be  driven  by  horsepower,  is 
given  in  Fig.  9. 

Such  a  machine  will  sink  a  3-inch  well  to  a  depth  of  500 
feet  and  larger  sizes  proportionately  less  depth. 

ROTARY  MACHINES. — Where  quicksand  or  extremely 
loose  alluvial  material  is  encountered,  or  on  the  other  hand 
where  holes  are  to  be  drilled  in  solid  rock,  rotary  drilling 
machines  are  found  of  great  convenience  and  economy. 
Such  a  machine  may  be  made  by  adding  a  special  attach- 
ment to  a  spudding  machine.  In  the  rotary  machine  the 
well  casing  is  rotated  and  the  material  under  the  cutting 
edge  is  forced  out  and  passes  to  the  surface  around  the 
outside  of  the  casing  under  the  action  of  water  forced  in 
at  the  top  of  the  casing  under  pressure.  The  water  not 
only  removes  the  material  in  the  path  of  the  casing,  but 


FIG.  9. — A  jetting  machine  of  small  size. 


WELL   SINKING 


49 


also  erodes  a  passage  around  it,  allowing  it  to  sink  easily 
and  rapidly.  Where  rock  must  be  penetrated,  either  a 
tempered  steel  saw-tooth  cutting-edge  tool  is  placed  on  the 


11 
*  I 
8  3 


—i    .*+ 

11 

•8* 


II 
<« 

0 


bottom  of  the  pipe,  or  a  special  hollow  tool  is  used,  the 
cutting  edge  of  which  is  studded  with  some  hard  material 
like  the  diamond,  though  the  diamond  drill  is  being  super- 


50  PRACTICAL   IRRIGATION   AND   PUMPING 

seded  by  those  in  which  carborundum  and  such  materials 
are  used.  In  this  method  of  boring  through  rock,  a  core  is 
left  inside  of  the  pipe  or  tool  and  is  removed  from  time  to 
time  for  examination  of  the  kind  of  material  being  pen- 
etrated. Such  a  method  of  drilling  is  of  evident  value  in 
prospecting  work,  and  is  very  generally  employed,  also,  in 
investigating  the  character  of  underground  strata  prepar- 
atory to  the  building  of  high  dams,  etc.  The  rotary  scheme 
of  drilling  is  particularly  well  adapted  to  the  sinking  of 
8-inch  casings  to  depths  of  100  feet  or  less,  such  as  comprise 
most  of  the  irrigation  wells.  Moreover,  since  it  lends  itself 
particularly  to  the  driving  of  casings  into  quicksand  for- 
mations it  is  of  much  use  where  churn  drilling  and  sand 
bucketing  fails  or  is  very  slow  indeed.  Again,  since  the  cas- 
ing sinks  of  its  own  weight,  it  is  possible  to  jack  it  up  easily 
after  a  strainer  of  the  Porcher  type  has  been  placed  in 
position.  Although  it  has  some  disadvantages,  it  certainly 
cannot  be  denied  that  the  rotary  process  of  drilling  possesses 
great  merit  for  the  drilling  of  large,  shallow  wells  for  irri- 
gation pumping.  A  machine  for  such  work  as  made  by  the 
American  Well  Works  and  adapted  to  be  attached  to  a  four- 
leg  derrick  and  driven  by  chain  from  a  steam  or  gas  engine, 
is  shown  in  Fig.  10  and  Fig.  n. 

Operation  of  Well  Sinking. — The  actual  operation  of 
well  sinking  need  not  be  gone  into  with  much  detail,  since 
no  two  problems  are  ever  just  alike  and  since  it  would  be 
useless  to  point  out  here  all  the  various  operations  which 
must  be  gone  through  and  the  precautions  which  must  be 
observed  in  the  actual  work.  The  man  who  expects  to  drill 
his  own  well  should  make  it  a  point  to  visit  a  well  being 
drilled  by  some  experienced  well  driller,  and  both  by  ob- 
servation and  discreet  questioning,  learn  as  much  as  possible 
of  the  method  before  attempting  anything  in  a  similar  way 
himself.  In  general  the  better  way,  of  course,  as  before 


WELL   SINKING  51 

stated,  is  to  contract  the  work  to  a  man  with  a  good,  prac- 
tical knowledge  of  the  matter  rather  than  to  attempt  to 
do  the  work  oneself  except  where  the  well  is  to  be  small  and 
comparatively  shallow.  Some  hints,  however,  to  the  man 
who  must  for  any  reason  attempt  the  work  himself  may  not 
be  out  of  place  here. 

The  Well  Pit. — Where  a  centrifugal  pump  is  to  be  used, 
it  should,  for  reasons  which  will  be  explained  later,  be  set  as 
near  the  water  level  as  possible,  and  this  usually  necessi- 
tates placing  the  pump  at  the  bottom  of  a  pit  excavated 
to  the  level  of  standing  water.  Such  a  pit  should  be  dug 
prior  to  the  coming  of  a  well  driller,  since  wells  are  con- 
tracted for  on  the  basis  of  so  much  per  foot,  and  there  is  no 
advantage  in  paying  for  the  driving  of  a  pipe  from  the 
surface  and  subsequently  excavating  around  it  down  to 
water  level,  and  removing  the  casing  between  that  point 
and  the  surface.  The  pit  may  be  round  or  square,  but 
since  it  should  be  lined  to  prevent  caving  (in  most  materials), 
it  is  obvious  that  its  shape  will  be  determined  largely  by 
the  material  used  in  the  lining.  If  lumber  is  used,  the 
square  or  rectangular  shape  is  best,  but  if  it  be  lined  with 
brick,  concrete,  or  rubble  masonry,  less  material  will  be 
used  and  a  stronger  curb  will  result  from  the  adoption  of  a 
circular  section.  The  dimensions  of  the  pit  will  be  deter- 
mined largely  by  the  dimensions  of  the  pump  to  be  used, 
but  in  no  case  should  it  be  less  than  6  feet  in  diameter  or 
on  a  side.  For  depths  less  than  30  feet  in  firm  material,  the 
pit  may  be  dug  and  afterwards  lined  or  curbed,  but  for 
greater  depths  the  danger  of  caving  should  necessitate 
either  the  use  of  a  temporary  lining  or  a  permanent  lining 
which  sinks  as  excavation  progresses  and  is  constantly 
built  upon  at  the  top.  In  the  digging  of  the  pit  the  use  of 
a  well-machine  will  be  found  convenient  to  facilitate  the 
removal  of  material  excavated  and  for  lowering  shoring 


52  PRACTICAL   IRRIGATION   AND   PUMPING 

material,  timbers,  and  curb  material,  etc.,  in  the  pit  during 
construction. 

Practice  is  divided  on  the  question  of  whether  it  is  more 
economical  to  drive  the  pipe  from  the  bottom  of  the  pit 
or  to  continue  the  pipe  to  the  ground  surface  and  drive  from 


FIG.  11. — -A  rotary  drilling  rig  in  operation  in  Texas.  An  unusually  rapid  means 
of  drilling  large  wells  in  alluvial  formation.  Has  drilled  30-inch  wells  250  feet  deep 
in  8  days,  including  setting-up  and  disassembling  of  rig,  no  rock  being  encountered. 

that  level.  In  the  latter  case  an  extra  length  of  pipe  equal 
to  the  depth  of  the  pit  must  be  furnished,  but  there  is  the 
advantage  of  the  greater  weight  on  the  driving  shoe  when 
the  pipe  must  be  driven,  and  also  when  it  becomes  necessary 
to  turn  it  (as  frequently  happens  even  in  churn  drilling)  it 
is  a  much  easier  operation  when  the  pipe  extends  above 
ground  level.  Of  course  in  rotary  drilling  the  pipe  must  of 
necessity  extend  to  or  above  ground  level. 


WELL   SINKING 


53 


Weights  of  Pipe. — In  the  matter  of  purchase  of  pipe  it  is 
well  to  have  in  mind  the  fact  that  wrought-iron  or  steel  pip- 
ing is  made  in  several  weights.  What  is  known  as  standard 
or  merchant  weight  pipe  is  the  common  weight.  There  is 

TABLE  VI 
STANDARD  STEAM,  GAS,  AND  WATER  PIPE 


Nominal 
Inside  Diam. 
Inches 

Actual 
Outside 
Diam. 

Nominal 
Weight  per  Ft. 
Pounds 

Threads  per 
Inch 

Nominal 
Outside  Diam. 
Couplings 

H 

.40 

.40 

27 

.562 

H 

•54 

.42 

18 

.718 

y* 

•675 

•56 

18 

•875 

x 

.84 

.84 

14 

I.OOO 

x 

1.05 

I.  12 

14 

1.312 

i 

I.3I5 

1.67 

UK 

1.625 

i# 

1.66 

2.24 

Uj/2 

1.937 

iji 

1.9 

2.68 

\\1A 

2.125 

2 

2-375 

3.6i 

8 

2.750 

2^ 

2.875 

5-74 

8 

3.250 

3 

3-5 

7.54 

8 

3-812 

VA 

4- 

9.00 

8 

4-375 

4 

4-5 

10.66 

8 

4-937 

4^ 

5- 

12.49 

8 

5-406 

5 

5-563 

14-50 

8 

6.031 

6 

6.625 

18.76 

8 

7-406 

7 

7.625 

23-27 

8 

8.250 

8 

8.625 

28.18 

8 

9.187 

9 

9.625 

33-70 

8 

10.50 

10 

io.75    . 

40.00 

8 

11.68 

ii 

12. 

45-00 

8 

12.12 

12 

12-75 

49.00 

8 

13.87 

also  a  grade  or  weight  known  as  artesian-well  casing,  which 
is  much  lighter  for  the  same  nominal  size  than  standard  pipe. 
Standard  pipe  is  always  designated  by  its  nominal  inside 
diameter,  and  for  the  sake  of  consistency  casing  should  be 
measured  in  the  same  way.  It  will  be  found,  however, 


54 


PRACTICAL  IRRIGATION  AND  PUMPING 


that  sizes  3-inch,  4-inch,  and  5-inch  may  mean  either 
inside  or  outside  diameter;  thus  a  5 -inch  casing  may 
mean  one  whose  internal  diameter  is  4^  inches  and  ex- 
ternal diameter  5  inches,  or  one  whose  internal  diameter  is 


TABLE  VII 
ARTESIAN  WELL  CASING 


Nominal 
Inside 
Diameter 

Actual 
Outside 
Diameter 

Nominal  Weight 
per  Foot 
Pounds 

Threads  per 
Inch 

Nominal 
Outside  Diam. 
Couplings 

2 

2  5-^ 

2.22 

14 

2.69 

2  5^ 

2  3^ 

2.82 

14 

2.88 

2  1/2 

2  ^4 

3-13 

14 

3-19 

2^4 

3 

3-45 

14 

3-50 

3 

3K 

4.10 

14 

3-78 

3>4 

3K 

4-45 

14 

4.00 

3K 

3X 

4.78 

H 

4-25 

3K 

4 

5-56 

14 

4-63 

4 

4X 

6.00 

14 

4-69 

4^4 

4>^ 

6.36 

14 

4-94 

4/^ 

4X 

6-73 

H 

5-22 

4^ 

5 

7.80 

14 

5-56 

5 

sA 

g 

8.20 

8.62 

14 
14 

5-78 
6.06 

5% 

6 

10.46 

14 

6-63 

6^ 

6^ 

11.58 

14 

7-13 

6^8 

7 

12.34 

14 

7-69 

7>i 

7/^ 

13-55 

14 

8.22 

7% 

8 

I5-4I 

II# 

8-63 

8>£ 

8^ 

16.07 

II# 

9-31 

8% 

9 

17.60 

H>£ 

9-75 

9% 

10 

21.90 

»'# 

10.81 

5  inches  and  external  diameter  is  5^  inches.  It  is  advisable, 
therefore,  in  ordering  casing  that  the  words  "external  diam- 
eter" or  "  internal  diameter, "  as  the  case  may  be,  follow  the 
particular  size  desired.  The  above  tables  give  the  sizes 
and  weights  of  standard  piping  and  casing  which  will  show 


WELL   SINKING  55 

the  distinction  in  sizes  very  clearly,  as  well  as  the  compar- 
ative weights  per  foot  for  the  same  nominal  sizes. 

Tapering  of  Borings. — If  a  well  has  been  started  with 
standard  pipe  and  after  reaching  a  certain  depth  cannot  be 
driven  further  because  of  friction,  the  boring  is  usually 
continued  by  dropping  down  inside  the  pipe  a  smaller- 
sized  casing  or  pipe  (usually  the  former),  of  such  diameter 
that  couplings  on  the  inner  pipe  will  allow  it  to  pass  freely 
but  at  the  same  time  give  a  fairly  close  fit.  Thus  8-inch 
standard  pipe  has  an  actual  internal  diameter  of  7.98  inches 
so  that  6fi  inches  (inside  diameter)  casing,  the  couplings 
£>f  which  are  7.69  inches  outside  diameter,  will  be  able  to 
enter  the  pipe  without  difficulty. 

Special  joints  may  be  secured  on  piping  such  as  "  in- 
serted joints,"  "flush  joints,"  etc.,  the  object  of  such  joints 
being  to  make  a  smooth  exterior  surface  and  thus  lessen 
the  friction  in  driving  which  arises  with  piping  having  the 
usual  coupling  joints.  Such  special  joints  cost  extra  and 
since  they  are  weaker  than  standard  pipe  couplings  should 
not  be  used  except  in  special  cases.  They  can  only  be 
obtained  on  the  larger  sizes.  Where  a  pipe  is  to  be  sub- 
jected to  heavy  driving,  a  special  coupling  joint  can  be 
obtained  which  by  the  use  of  specially  long  threaded  ends 
and  special  couplings  allows  the  ends  of  adjacent  pipe 
sections  to  butt  together,  thus  preventing  threads  being 
stripped  and  couplings  split,  as  sometimes  occurs  during 
heavy  driving  with  ordinary  couplings.  For  very  deep 
drilling,  grades  of  pipe  known  as  heavy  or  extra  heavy 
should  be  used  with  special  joints  if  the  expense  is  not 
prohibitive. 

As  may  be  seen  from  the  above  tables,  standard  pipe 
weighs  about  double  the  artesian-well  casing  of  the  nearest 
equivalent  nominal  internal  diameter,  and  it  usually  costs 
about  one  and  one-half  times  as  much  as  the  casing.  Where 


56  PRACTICAL   IRRIGATION   AND   PUMPING 

the  well  is  a  great  distance  from  a  point  of  shipment  the 
freight  charges  on  casing  will  be  very  much  less  than  on  the 
same  length  of  standard  pipe,  so  that  casing  is  much  the 
cheaper  delivered  at  the  site  of  the  well.  It  must  be  remem- 
bered, however,  that  casing  cannot  be  driven,  without  great 
risk  of  injury,  to  a  depth  greater  than  100  feet  by  "  spud- 
ding," that  because  of  its  lighter  weight  it  does  not  sink 
as  readily  as  pipe,  and  it  is  much  more  easily  injured  in 
assembling.  Another  feature  of  importance,  particularly 
in  steel  casing  where  the  water  is  alkaline,  is  the  ease  with 
which  electrolytic  action  causes  serious  holes  to  be  eaten 
in  the  thinner  casing,  although,  of  course,  it  will  only  be  a 
matter  of  somewhat  longer  time  when  standard  pipe  will 
be  similarly  injured.  In  such  water  the  only  safety  consists 
in  specifying  and  being  sure  one  gets  the  purest  kind  of 
wrought-iron  pipe. 

Stovepipe  Casing. — A  method  of  well  drilling  familiar  to 
Californians,  but  not  much  used  outside  of  that  state,  is 
that  known  as  the  "stovepipe"  method.  It  is  used  with 
considerable  success  in  alluvial  material,  but  cannot  be 
recommended  where  coarse  gravel  or  boulders  are  likely  to 
be  encountered.  The  casing  consists  of  riveted  steel  sec- 
tions built  up  in  a  double  layer,  the  outer  telescoping  over 
the  inner  and  breaking  joints,  thus  making  the  riveting  of 
adjoining  sections  unnecessary.  A  cutting  section  of  heavier 
sheet  steel  is  provided  on  the  lower  end,  and  the  whole  is 
sunk  by  ordinary  spudding  methods,  except  that  the  casing 
is  forced  downwards  by  hydraulic  jacks.  As  a  section  is 
lowered,  more  of  the  stovepipe  sections  are  added.  Depths 
in  excess  of  1,000  feet  have  been  attained  by  this  method. 
The  most  interesting^feature  of  the  method  is  that  by  means 
of  a  special  cutting  tool  lowered  inside  the  casing  upon 
completion  of  the  well,  vertical  slits  are  cut  in  the  casing 
opposite  those  strata  which  the  driller's  log  indicates  are 


WELL   SINKING  57 

water-bearing,  thus  solving  the  question  of  a  strainer,  and 
insuring  that  the  strainer  will  be  exactly  where  wanted.  It 
is  not  unlikely  that  this  same  idea  might  be  applied  success- 
fully to  the  perforation  of  artesian-well  casing  which  would 
not  be  very  much  more  difficult  to  cut  than  two  layers  of 
No.  12  sheet  steel,  particularly  in  the  larger  sizes  of  casing. 
It  may  be  added  that  the  "stovepipe  method"  is  not  used 
for  borings  less  than  1 2  inches  in  diameter,  the  most  common 
size  being  14  inches. 


CHAPTER  VI 

PUMPS  AND  PUMPING  MACHINERY  AND   APPLIANCES 

IN  the  foregoing  chapters  we  have  discussed  methods  of 
arriving  at  an  approximate  estimate  of  the  amount  of  water 
required,  we  have  discussed  the  possibility  of  estimating  the 
probable  capacities  of  wells,  when  the  supply  must  be  taken 
from  an  underground  source,  and  we  have  given,  somewhat 
briefly  and  possibly  inadequately,  an  idea  of  the  method  by 
which  the  well  may  be  constructed  and  the  water  supply 
developed.  In  the  present  chapter  and  one  or  two  following, 
we  shall  describe  the  pumping  machinery  which  it  is  advisa- 
ble or  necessary  to  use  to  bring  the  supply  to  the  surface  or  to 
pump  it  from  the  source  to  the  point  at  which  it  is  desired 
the  water  shall  be  used. 

Caution  Needed  in  the  Selection  of  Pumps. — At  the  out- 
set we  desire  to  sound  a  note  of  warning  and  caution  to 
those  who  feel  themselves  competent  to  select  and  install 
their  own  machinery.  Nothing  is  more  commonplace  than 
a  pump,  and  probably  every  American  who  has  had  any 
experience  with  one,  no  matter  what  the  type,  has  an  in- 
ward conviction  that  he  could  invent  a  better  one,  the 
natural  result  being  that  inventive  geniuses  by  the  score 
have  invented  and  patented  pumps, — while  occasionally 
some  inventor  more  courageous  or  fortunate  than  the  rest 
succeeds  in  getting  his  ideas  into  concrete  form  and  on  the 
market.  The  curious  thing  about  all  such  devices  is  the 
absolute  assurance  of  those  interested  in  their  introduction 
that  they  will  surpass  anything  now  on  the  market  in  effi- 
ciency, durability,  and  general  excellence.  It  is  no  uncom- 

58 


PUMPS   AND   PUMPING   MACHINERY   AND   APPLIANCES     59 

mon  thing  for  mechanical  efficiencies  of  95  per  cent,  to  be 
claimed,  and  an  enthusiastic  salesman  once  informed  the 
writer  that  he  was  sure  100  per  cent,  efficiency  could  be 
secured  in  the  use  of  his  pump  if  the  water  passages  and 
pipes  were  nickel-plated  to  reduce  the  friction  of  water  on 
iron.  One  needs  reflect  but  a  moment  to  appreciate  the 
absurdity  of  such  claims,  for  it  is  one  of  the  elementary 
principles  of  physics  that  no  machine  can  be  100  per  cent, 
efficient,  while  any  one  familiar  with  the  ordinary  processes 
of  manufacture  will  realize  that  even  relatively  moderate 
efficiencies  in  machinery  can  only  be  attained  by  refinements 
in  design,  materials,  and  manufacture  which  are  only  war- 
ranted when  the  saving  of  power  incident  to  the  use  of  the 
very  efficient  machine  will  pay  interest  on  the  difference  in 
cost  between  it  and  one  of  less  efficiency.  Other  important 
considerations  which  would  justify  or  condemn  the  use  of 
the  highly  efficient  machine  are  convenience  in  installa- 
tion and  use,  durability,  space  occupied,  weight,  etc. 

Pumps  which  have  been  Proposed. — Among  the  many 
pumps  which  at  one  time  or  another  have  been  brought 
forward  by  hopeful  geniuses  for  the  solution  of  the  problem 
of  irrigation  pumping  are:  Screw  pumps,  propeller  pumps, 
bucket  elevators,  air  lifts,  air  displacement  pumps,  and 
various  modifications  of  centrifugal  and  turbine  pumps, 
rotary  pumps,  balanced  plunger  pumps,  etc.  The  last 
named  was  conceived,  by  an  inventor  who  effected  by 
means  of  weights  on  the  end  of  a  lever  a  balancing  of  the 
column  of  water  on  top  of  the  pump  plunger,  so  that  ac- 
cording to  his  idea  it  would  require  no  more  power  to  pump 
a  given  quantity  of  water  through  5oo-foot  head  than 
through  50  feet.  All  of  these  pumps  will  actually  pump 
water,  and  many  of  them  have  some  merit,  but  the  great 
majority  are  found  by  mechanical  test  to  fall  far  below  the 
expectations  of  their  inventors,  while  many  are  extremely 


60  PRACTICAL  IRRIGATION  AND  PUMPING 

wasteful  of  power  and  have  efficiencies  of  from  25  to  50  per 
cent.  Such  pumps  waste  much  of  the  power  applied  to  them 
in  shock  and  churning  effects  of  the  water,  besides  purely 
mechanical  defects  causing  friction  and  eddy  losses. 

It  rarely  pays,  therefore,  for  the  man  who  desires  an 
efficient,  serviceable,  and  satisfactory  pumping  plant  to  be 
led  aside  and  induced  to  purchase  some  recently  devised 
and  comparatively  untried  pumping  device,  whose  manu- 
facturer attempts  to  catch  the  unwary  by  attractive  guar- 
antees of  low  cost  of  pumping.  Before  being  induced  to 
purchase  such  machinery  the  intending  purchaser  would 
do  well  to  demand  a  mechanical  test  of  the  pump  and  a 
report  upon  the  same  made  by  a  competent  and  reliable 
mechanical  engineer  whose  position  and  reputation  enable 
him  to  give  an  unbiased  opinion.* 

What  Should  Decide  the  Make  and  Type  of  Pump  to  Use? 
— A  decision  as  to  the  type  of  pump  to  adopt  for  a  partic- 
ular set  of  conditions  should  be  governed  somewhat  by  its 
reputation.  The  standard  pumps  now  on  the  market  have 
been  slowly  evolved  through  years  of  experience  and  experi- 
mentation on  the  part  of  skilled  designers  who  apply  the 


*  It  is  indeed  surprising,  not  only  how  quickly  the  news  of  a  new 
device  spreads,  but  how  eager  Western  people  are  to  apply  every  advance 
in  the  art  of  pumping  to  the  problem  of  cheap  irrigation  pumping. 
The  writer  was  surprised,  recently,  to  receive  a  letter  from  a  gentleman 
in  Utah  asking  the  opinion  of  the  writer  as  to  whether,  in  his  judgment, 
the  Humphrey  Gas  Pump  could  be  used  with  success  in  the  irrigation 
of  his  farm  of  about  100  acres.  The  writer  was  compelled  to  reply  that, 
however  interesting  and  successful  the  Humphrey  pump  might  be,  it 
seems  scarcely  possible  in  the  present  stage  of  its  development  to  adapt 
it  successfully  to  the  uses  of  an  irrigation  pump  on  a  comparatively 
small  farm  in  a  region  remote  from  coal  suitable  for  the  production  of 
producer  gas.  We  have  no  doubt,  however,  that  eventually  this  pump 
or  one  acting  on  the  same  principle  will,  when  made  in  the  right  sizes, 
be  of  value  in  the  solution  of  the  question  of  cheap  water  supply  for 
moderate  lifts. 


PUMPS  AND   PUMPING  MACHINERY  AND  APPLIANCES    6 1 

results  of  experience  in  years  of  practical  operation  to  the 
design  and  construction  of  their  pumps.  It  is  true,  of 
course,  particularly  in  the  case  of  centrifugal  pumps,  that 
there  are  stock  sizes  which  are  sold,  like  shelf  hardware, 
with  only  the  most  meagre  attention  to  the  particular 
conditions  under  which  they  are  to  operate.  Even  in  such 
cases,  however,  the  purchaser  may  be  sure,  if  the  pump  is 
made  by  a  reliable  manufacturer,  that  it  will  be  durable  and 
serviceable,  which  assurance  is  lacking  in  the  case  of  many 
of  the  so-called  "freak"  pumps  already  described.  The 
writer  must  not  be  considered  as  decrying  or  discouraging 
originality  in  pump  design,  but  the  pumping-plant  operator 
whose  profits  depend  upon  the  reliability  and  durability  of 
his  equipment  can  better  afford  to  adopt  and  use  standard 
machinery  than  act  as  an  experimental  agent  for  some  new 
and  comparatively  untried  device.  The  expense  of  experi- 
ments and  the  burden  of  failures  had  much  better  be  borne 
by  those  engaged  in  its  manufacture  than  by  the  purchaser, 
whose  livelihood  is  likely  to  depend  upon  its  successful 
operation.  If  a  purchaser  desires  the  high  economy  and 
efficiency  usually  claimed  by  promoters  of  new  styles  of 
pumps,  he  can  secure  the  same  or  higher  economy  in  more 
refined  machinery,  for  which,  however,  he  will  be  required 
to  pay  a  correspondingly  higher  price. 

The  fact  that  a  pump  will  actually  raise  water  is  no 
guarantee  of  its  efficiency,  that  pump  being  most  efficient 
which  raises  a  given  quantity  of  water  through  a  given  head 
with  a  minimum  power  consumption.  Until  a  new  pump  can 
be  shown  by  reliable  and  thorough  mechanical  tests  to  ex- 
ceed the  efficiency  of  standard  machinery,  it  should  be  let 
alone  by  the  irrigation  farmer,  unless  conclusive  evidence  can 
be  produced  that  it  is  more  reliable,  more  durable,  and 
very  much  lower  in  first  cost  than  a  standard  machine  which 
will  do  the  same  work  with  the  same  power  consumption. 


62  PRACTICAL   IRRIGATION  AND   PUMPING 

The  Standard  Types  of  Irrigation  Pumps. — There  are 
three  standard  types  of  pump  which  Western  practice  has 
shown  are  suitable  for  irrigation  work.  These  are  centrif- 
ugal pumps  or  turbine  pumps  (which  are  a  special  form  of 
centrifugal),  single  or  multi-cylinder  reciprocating  pumps, 
and  well  cylinders.  In  rice  irrigation  certain  forms  of  rotary 
pumps  have  been  used  with  such  success  that  they  might 
properly  be  called  standard  equipment.  Under  certain 
special  conditions  a  water-lift  or  bucket-and-chain  pump 
might  also  be  included. 

Each  of  these  types  of  pumps  is  best  adapted  to  a 
\  certain  set  of  conditions,  the  limits  of  which  are  very  well 
recognized,  though  unquestionably  the  limits  which  we 
shall  hereinafter  mention  will  be  called  in  question  by  those 
manufacturers  who  make  but  one  type  of  pump  and  who 
profess  to  believe  this  type  suitable  for  any  set  of  conditions 
without  regard  to  economy  of  operation,  capacity,  head,  or 
practical  difficulties  of  operation. 


CHAPTER  VII 

CENTRIFUGAL  PUMPS 

THE,  centrifugal  type  of  pump  enjoys  a  well-deserved 
popularity  with  those  who  have  to  solve  the  problems  of 
irrigation  pumping,  because  of  its  extreme  simplicity,  its 
low  price,  the  comparative  ease  with  which  it  may  be 
installed,  and  its  freedom  from  some  of  the  annoyances 
which  are  encountered  in  the  operation  of  other  types.  It 
is,  however,  in  the  small  and  stock  sizes  a  machine  of  low 
efficiency,  as  will  presently  be  pointed  out,  and  for  that 
reason,  where  the  cost  of  power  is  an  important  consider- 
ation, it  may  be  well  to  study  its  characteristics  with  some 
care  before  choosing  it  for  any  given  case. 

The  Centrifugal  Pump  Described. — In  its  simplest  form, 
the  centrifugal  pump  comprises  a  casing,  D,  inside  of  which 


FIG.  12. — The  parts  of  a  simple,  cheap  centrifugal  pump. 

is  rotated  a  runner  or  impeller.  The  impeller,  I,  as  shown 
in  the  figure  has  side  plates  between  which  are  cast  back- 
wardly  bending  vanes  V.  the  water  entering  the  impeller 

63 


64  PRACTICAL  IRRIGATION  AND   PUMPING 

through  an  opening  at  the  centre  on  the  far  side  of  the 
impeller  (not  shown  in  the  sketch)  and  being  ejected  at 
high  velocity  from  the  openings  around  the  periphery  of 
the  impeller,  thence  passing  through  the  flanged  outlet  O 
into  the  discharge  pipe.  The  diameter  of  the  opening  0 
determines  the  nominal  size  of  the  pump.  Thus  in  a  6-inch 
pump,  the  opening  0  is  approximately  6  inches  in  diam- 
eter. In  the  'cheek  plate  F  is  usually  a  babbitted  bearing 
to  support  the  shaft  of  impeller  and  a  stuffing  box  S  by 
which  air  is  prevented  from  entering  the  pump  and  de- 
stroying the  vacuum.  To  the  left  of  the  parts  shown  would 
be  a  pulley  mounted  on  the  shaft  (if  the  machine  be  belt- 
driven)  and  an  outboard  bearing.  There  is  also  usually  a 
thrust  bearing  provided  at  or  near  the  outer  end  of  the 
shaft  to  take  up  any  unbalanced  thrust  due  to  the  action 
of  the  water  on  the  blades  of  the  impeller  as  it  enters  the 
latter.  The  form  of  pump  shown  in  the  sketch  is  called 
the  horizontal  type;  those  in  which  the  shaft  is  vertical 
belong  to  the  vertical  type,  and  each  has  its  proper 
sphere  of  usefulness,  depending  upon  location,  as  herein- 
after explained.  The  type  of  impeller  shown  is  called 
the  closed  type,  but  some  excellent  makes  of  pumps  have 
what  is  termed  the  open  type  as  shown  in  Fig.  2 1 . 

The  relative  advantage  of  the  two  types  of  impellers  is 
not  well  determined,  although  it  is  to  be  noted  that  all  of 
those  pumps  in  which  a  determined  effort  is  made  by  the 
designers  to  secure  a  higher  efficiency  than  is  obtained  in 
the  ordinary  centrifugal  pump  have  enclosed  impellers  with 
carefully  moulded  and  shaped  water  passages.  For  total 
heads  or  lifts  in  excess  of  75  or  100  feet  the  speed  at  which 
the  simple  centrifugal  pump  must  be  run  becomes  so  ex- 
cessively high  that  two  or  more  simple  pumps  must  be 
operated  in  series;  that  is,  the  discharge  of  one  pump  is 
led  to  the  suction  of  the  next,  and  thence  into  the 


CENTRIFUGAL   PUMPS 


discharge  pipe.  The  quan- 
tity of  water  obtained  by 
such  a  combination  is 
about  the  same  as  that 
from  a  single  pump  and 
the  head  through  which 
water  may  be  lifted  for  a 
given  speed  of  rotation  is 
roughly  as  many  times 
that  for  a  single  pump  as 
there  are  stages,  thus  in 
a  two-stage  pump  the 
head  attainable  would  be 
about  twice  that  in  a  |p 
single-stage  pump.  Multi- 
stage pumps  may  be  built 
as  two  or  more  separate 
simple  pumps  connected 
together  by  suitable  pip- 
ing and  run  by  the  same 
shaft  or  there  may  be  a 
number  of  runners  in  the 
same  casing  with  suitably 
shaped  passages  to  con- 
vey the  water  from  around 
the  periphery  of  one  im- 
peller to  the  centre  of  the 
next.  Such  pumps,  be- 

FIG.  13. — Phantom  view  of  a  special  type 
of  belt-driven  multi-stage  vertical  centrifugal 
pump  arranged  to  be  lowered  inside  a  large- 
sized  casing  sunk  by  rotary  methods,  and  tak- 
ing water  from  a  driven  well  of  depth  within 
200  feet.  Is  entirely  self-contained  and  does 
away  with  open  pit.  A  later  type,  made  by 
same  manufacturer,  may  be  installed  in  12-inch 
casing  and  has  delivered  1,000  G.P.M. 


FIG.  13. 


00  PRACTICAL   IRRIGATION  AND   PUMPING 

cause  of  the  complexity  of  the  patterns  from  which  they 
are  made  and  the  complex  cores  and  difficult  castings  in- 
volved are  somewhat  more  expensive  than  the  combina- 
tions of  simple  pumps.  In  following  pages  are  views  of 


horizontal  simple  and  multi-stage,   as    well  as  of  the  ver- 
tical types. 

Specifications  for  Centrifugal  Pumps. — For  the  ordinary 


CENTRIFUGAL  PUMPS  ,    67 

small  individual  installation,  it  is  idle,  perhaps,  to  suggest 
specifications  which  should  govern  the  purchase  of  pumps, 
for  several  reasons :  First,  the  average  individual  buys 
upon  the  reputation  of  a  pump  or  upon  its  durability  and 
serviceability  in  some  instance  which  has  come  under  his 
direct  observation,  frequently  regardless  of  mechanical 
details  or  efficiency;  second,  the  pump  he  buys  is  usually 
of  such  size  that  it  comes  within  the  range  of  stock  sizes 
and  it  would  be  very  difficult  and  expensive  to  secure  a 
single  machine  embracing  other  than  the  usual  stock 
details.  Except,  therefore,  in  cases  where  a  large  number  of 
small  pumps  are  bought  at  one  order  for  some  co-ordinated 
scheme  of  pumping  it  is  useless  to  attempt  to  frame  speci- 
fications to  which  pump  builders  may  be  expected  to  care 
to  conform.  It  may,  however,  not  be  out  of  place  to 
enumerate  certain  essential  features  which  an  efficient  and 
durable  centrifugal  pump  should  comprise  even  in  com- 
paratively small  sizes  and  which  should  govern  the  selection 
and  purchase  of  machinery  for  any  but  the  cheapest 
central  station  plants. 

Pump  Case. — To  be  of  close-grained  cast-iron,  free  from 
blow-holes  and  shrinkage  cracks.  Should  be  suitably 
reinforced. with  ribs  and  flanges  in  sizes  over  6  inches  and 
with  discharge  heads  greater  than  75  feet.  The  pump 
case  should  be  divided  through  the  centre  line  of  the  shaft 
in  a  plane  affording  the  greatest  ease  of  removal  of  half  of 
case,  to  permit  inspection  and  cleaning  of  interior  of  case 
and  of  impeller,  without  disturbance  to  the  suction  or 
discharge  piping  or  connections.  This  is  of  special  im- 
portance in  the  case  of  pumps  taking  water  from  a  canal 
or  river  where  weeds,  fish,  and  trash  of  all  kinds  may  be 
taken  in  with  the  water  through  the  suction  pipe  and 
cause  serious  clogging  and  interference  with  operation  of 
pump.  With  solid-case  pumps  the  job  of  taking  apart  a 


I . 


ft 


SI 


CENTRIFUGAL  PUMPS  69 

pump  to  clean  and  inspect  it,  is  one  involving  much  time  and 
labor.  With  split-case  pumps  this  is  comparatively  simple. 

Suction. — For  all  except  very  small  sizes,  the  suction 
opening  of  single-stage  pumps  should  be  double,  allowing 
water  to  enter  impeller  from  both  sides.  This  avoids 
end  thrust  as  with  side  •  suction  pumps,  in  which  it  must 
be  resisted  by  thrust  bearings  and  is  a  constant  source  of 
power  loss  in  spite  of  the  various  hydraulic  balancing 
arrangements  in  use.  The  suction  passage  should  be  of 
ample  size  with  gradually  curving  flow  lines  and  be  self- 
contained  within  the  case. 

Impeller. — For  large  pumps  this  should  be  of  bronze, 
preferably  of  the  composition  known  as  Government 
Bronze.  This  is  resistant  to  corrosion  and  under  the 
scouring  action  of  water  acquires  a  smooth  surface  which 
greatly  reduces  the  energy  loss  in  friction  of  water  passing 
at  high  velocity  through  the  impeller. 

Packing  Joint  and  Clearance. — The  clearance  between 
the  pump  case  and  impeller  at  the  packing  joint  should 
be  a  running  fit  and  at  this  joint  preferably  should  be 
bronze  rings  that  may  be  replaced  when  worn.  In  the 
more  elaborate  pumps  a  labyrinth  packing  is  sometimes 
introduced  at  this  point. 

Shaft. — The  shaft  should  be  of  forged,  open-hearth 
steel  and  of  ample  strength  to  resist  torsion,  bending,  and 
other  stresses.  Where  it  passes  through  the  stuffing  box 
or  boxes  and  on  the  inside  of  the  pump  case  it  should  be 
protected  from  wear  by  a  removable  bronze  sleeve. 

Stuffing  Boxes. — These  should  be  arranged  for  water 
seal  and  soft  packing  and  the  glands  should  be  of  bronze. 
In  the  larger  pumps  glands  should  be  split  to  facilitate 
complete  removal  without  disturbing  other  parts. 

Bearings. — In  the  bearings  only  the  best  grade  of 
babbit  should  be  used.  In  horizontal  pumps  the  babbit 


7O  PRACTICAL   IRRIGATION   AND   PUMPING 

should  be  in  split  shells,  which  may  be  removed  without 
disturbing  other  parts.  The  bearings  should  be  ring 
oiling  with  ample  oil  reservoir  provided  with  glass  oil- 
gauge.  The  bearing  pedestal  construction  should  be  rigid, 
and  so  formed  as  to  prevent  throwing  of  oil.  Ample 
thrust  collars  should  be  provided  in  all  horizontal  double- 
suction  pumps  to  take  up  any  slight  unbalancing  due  to 
clogging  of  one  side  of  impeller.  For  side  suction,  single- 
stage  pumps  of  large  size  the  thrust  bearing  should  be  of 
marine  type  and  provided  with  water  jackets.  In  vertical 
pumps  a  ball-  or  roller-bearing  of  ample  size  should  be 
provided  to  carry  full  weight  of  shafting,  impeller,  and 
also  motor  armature,  in  electrically  driven  types,  in  addi- 
tion to  any  unbalanced  thrust  due  to  water  pressure. 

Flexible  Couplings. — These  should  always  be  pro- 
vided between  motor  and  pump  in  direct-connected  units, 
to  eliminate  wear  on  bearings  due  to  slight  inaccuracies 
in  alignment. 

Inspection  and  Tests. — For  a  large  pumping-plant  proj- 
ect careful  specifications  covering  points  above  enumerated 
should  always  be  drawn  up  by  a  competent  mechanical 
engineer  and  the  contract  should  permit  inspection  of  the 
machinery  during  construction,  to  see  that  mechanical  de- 
tails are  built  according  to  specifications.  Finally,  it  should 
be  stipulated  that  the  pump  or  pumps  should  be  tested  at 
the  factory  previous  to  delivery  under  the  conditions  of 
speed  and  head  at  which  they  are  to  operate  and,  if  pos- 
sible in  the  case  of  electric  drive,  should  be  tested  with 
the  same  motors  by  which  they  are  to  be  operated.  The 
results  of  the  test  should  be  plotted  on  cross-section  paper 
and  curves  drawn  showing  the  characteristics  of  the  pump. 
These  curves  should  be  considered  as  guarantee  of  per- 
formance and  should  be  checked  by  test  under  running 
conditions  subsequent  to  completion  of  plant. 


CENTRIFUGAL  PUMPS  71 

Characteristics  of  Centrifugal  Pumps. — Those  who  now 
operate,  as  well  as  those  who  expect  to  operate  centrifu- 
gal pumps  should  have  some  familiarity  with  the  mechani- 
cal characteristics  of  such  machinery,  for  it  is  undoubtedly 
true  that  much  of  the  dissatisfaction  we  find  among  those 
who  use  these  pumps  has  been  due  to  an  attempt  to  operate 
them  under  conditions  for  which  they  were  not  designed 
or  well  adapted.  As  will  be  noted  from  the  brief  description 
already  given,  the  centrifugal  pump  differs  from  a  reciprocat- 
ing pump,  with  which  most  of  us  are  familiar,  in  having  no 
piston  or  plunger  and  no  valves.  Its  action  evidently,  there- 
fore, depends  upon  the  whirling  motion  imparted  to  the  water 
by  the  rapidly-rotating  impeller.  Simple  as  this  action  may 
seem,  the  fact  remains  that  although  many  voluminous  works 
have  been  written  upon  the  subject  and  many ^  and  some- 
times conflicting^  theories  advanced,  no  formula  or  method 
4ias  yet  been  devised  by  which,  with  the  speed  of  the  impel- 
ler and  the  size  and  proportions  of  the  impeller  and  casing 
given,  it  is  possible  to  figure  the  capacity  of  a  pump  or  its 
efficiency.  What  is  known  delTnitely  of  the  action  of  centrif- 
ugal pumps  has  been  determined  almost  entirely  by  experi- 
ment and  in  designing  a  new  pump  to  give  certain  desired 
characteristics,  the  designer  is  helped  but  very  little  by 
theory,  and  must  project  largely  his  knowledge  of  the 
action  of  existing  pumps  to  the  new  design.  By  this  process 
of  evolution,  centrifugal  pumps  are  continually  being  im- 
proved upon  and  higher  efficiencies  attained,  but  even  in 
those  of  most  advanced  design  there  occur  obscure  losses 
in  energy  due  to  friction,  shock,  or  impact,  secondary 
whirling  effects  or  eddies  and  leakage  of  water  through 
clearance  spaces  which  materially  cut  down  the  mechani- 
cal efficiency  of  the  machine  and  either  entirely  upset  the 
theoretical  notions  which  attempt  to  explain  its  action,  or 
by  reason  of  their  obscurity  make  the  constants  impossible 


72  PRACTICAL   IRRIGATION  AND   PUMPING 

of  determination  in  any  formula  in  which  these  losses  are 
recognized  and  allowed  for. 

What  the  Plant  Designer  or  Operator  Must  Know. — So 
far  as  the  operator  of  a  centrifugal  pumping  plant  is  con- 
cerned, and  particularly  the  man  designing  such  a  plant  or 
intending  to  use  centrifugal  pumps,  he  is  interested  not  so 
much  in  questions  of  the  design  of  the  pumps  themselves 
as  in  what  the  pumps  that  he  can  buy  will  do  under  a  given 
set  of  conditions.  Unfortunately  he  is  not  greatly  assisted 
in  securing  such  knowledge  by  the  information  which  may 
be  gleaned  from  a  manufacturer's  catalogue  containing 
descriptions  and  ratings  of  their  stock  pumps.  What  a 
purchaser  desires  to  know  is  what  speed  is  required  to  force 
water  through  a  given  head,  what  discharge  may  be  ex- 
pected at  that  head,  and  what  actual  horse-power  is  re- 
quired under  those  conditions  to  operate  the  pump.  The 
manufacturers'  rating  as  given  for  a  particular  size  of  pump 
is  usually  what  is  known  as  "the  economic  capacity," 
which  is  a  term  of  doubtful  meaning  and  of  very  little  use 
to  a  pump  purchaser,  for  nothing  is  usually  said  as  to 
whether  this  capacity  is  the  maximum  attainable,  which 
may  be  at  high  speed  and  low  head  or  is  that  capacity 
which  is  secured  under  conditions  of  maximum  efficiency. 
It  is  the  peculiar  characteristic  of  centrifugal  pumps  that 
the  capacity  is  a  variable  depending  upon  the  speed  at  which 
it  is  run,  and  the  total  head  against  which  it  operates. 
Conversely,  every  centrifugal  pump  when  run  at  a  certain 
speed  will  give  a  certain  discharge  at  a  certain  head.  If 
the  speed  be  increased  with  the  head  constant,  the  dis- 
charge will  be  increased  according  to  a  definite  law,  and  if 
the  speed  be  maintained  constant  and  the  head  be  decreased, 
the  discharge  will  generally  increase.  Furthermore,  every 
centrifugal  pump  has  a  definite  head  for  different  speeds  at 
which  it  operates  most  economically  from  the  standpoint 


CENTRIFUGAL  PUMPS 


73 


of  power  consumption  and  in  order  to  force  the  water 
through  this  head  this  particular  speed  should  be  used,  if, 
as  is  frequently  the  case,  the  cost  of  power  is  the  most 
important  factor  in  the  cost  of  operation. 


to  £  T3  S 

tlh 


The  Efficiency  of  the  Pump. — The  efficiency  of  a  centrif- 
ugal pump,  as  of  every  other  pump  or  any  mechanical  con- 
trivance transforming  mechanical  work  into  another  form 


74 


PRACTICAL   IRRIGATION  AND   PUMPING 


of  energy,  is  the  ratio  of  the  effect  to  the  cause,  or  in  the 
case  of  a  pump  we  may  define  it  as: 

Energy  in  moving  water 
Efficiency  =  — 

Energy  supplied  pump. 

The  energy  in  the  moving  water  is  the  product  of  the 
weight  of  water  elevated  in  a  given  time  multiplied  by  the 


A— 


VIEW 

ROM  SUCTION 
END  SHOWING 
SECTION  OF  CASING 
IMPELLER  EXPOSED 


SHOWING  SECTION 
THROUGH  LINE  A-B 


FIG.  17. — Cross-sections  of  2K-inch  Pump,  Serial  No.  1.   (See  Diagram  5.) 

total  head  in  feet  through  which  the  water  is  raised.  Thus 
a  pump  elevating  continuously  450  gallons  of  water  per 
minute  through  a  total  head  of  8.8  feet  gives  energy  to  the 
water  equivalent  to  one  horse-power  or  33,000  feet-pounds 
per  minute.  If  the  motor  or  engine  by  which  the  pump  is 
run  delivers  two  horse-power  to  such  a  pump  the  efficiency 


CENTRIFUGAL  PUMPS 


75 


will  be  50  per  cent,  and  one-half  of  the  power  delivered  by 
the  engine  will  be  lost  in  useless  churning  and  fluid 
friction  effects  in  the  pump  and  by  mechanical  friction  in 
its  bearings  and  stuffing  box.  Just  as  the  capacity  of  a 


SHOWING 

UCTION  END  OF  CASING 
REMOVED  WITW  THE 
IMPELLER  EXPOSED 


SECTION  AT  A-B 


FIG.  18. — Cross-sections  of  2-inch  Pump,  Serial  No.  2.   (See  Diagram  6.) 

centrifugal  pump  is  a  variable,  so  also  is  the  efficiency,  and 
for  different  heads  and  capacities  we  have  different  efficien- 
cies, all  varying  according  to  certain  laws.  For  any  given 
speed  there  will  be  a  certain  head  at  which  the  efficiency 
will  be  a  maximum,  and  a  knowledge  of  these  facts  is 


76 


PRACTICAL    IRRIGATION   AND   PUMPING 


necessary  to  intelligent  selection  of  a  pump  for  a  given 

purpose  and  to  insure  efficient  operation  after  it  is  installed. 

Pump   Curves. — In   the   following  pages   are   given   a 

number  of  diagrams  which  show  the  characteristics  of  sev- 


A- 


VIEW  FROM 

SUCTION   END 

SHOWING  SECTION 

OF  IMPELLER 

AND  CASING 


SECTION  THROUGH 
A-B 


FIG.  19. — Cross-sections  of  4-inch  Pump,  Serial  No.  3.    (See  Diagram  7.) 

eral  pumps  in  a  series  of  tests  made  under  the  direction  of 
the  writer  in  an  investigation  to  determine  various  facts 
relative  to  the  performance  of  stock  sizes  of  centrifugal 
pumps  such  as  are  commonly  used  in  irrigation  work. 


CENTRIFUGAL  PUMPS 


77 


•itf-pBOH  TOOJ 

§     8      8     g.     8     3     3     % 


78 


PRACTICAL   IRRIGATION  AND   PUMPING 


CENTRIFUGAL  PUMPS 


79 


8o 


PRACTICAL   IRRIGATION   AND   PUMPING 


CENTRIFUGAL  PUMPS 


81 


82 


PRACTICAL  IRRIGATION  AND  PUMPING 


CENTRIFUGAL  PUMPS 


84 


PRACTICAL   IRRIGATION  AND   PUMPING 


The  preceding  diagrams  give  the  following  information : 
(i)  The  discharge  in  gallons  per  minute  for  various  speeds 
when  total  heads  are  given.  (2)  The  mechanical  efficiencies 


at  different  speeds.  (3)  The  horse-power  required  to  be 
delivered  to  the  pump  in  order  that  different  quantities 
per  minute  may  be  discharged  through  different  total 


CENTRIFUGAL  PUMPS  85 

heads.     Some    of    the    diagrams    also    give    the    speeds 
which  should  be  used  to  give  maximum   efficiencies   at 


SHOWING 

SE'CTICN  OF  CASING 
WITH  IMPELLER  EXPOSED 


FIG.  21. — Cross-sections  of  6-inch  Pump,  Serial  No.  8.    (See  Diagram  9.) 

different  total  heads  and  the  corresponding  horse-power 
input.* 

*  The  names  of  the  makers  of  the  pumps  corresponding  to  the  dia- 
grams are  withheld  for  obvious  reasons. 


86 


PRACTICAL  IRRIGATION  AND  PUMPING 


The  Selection  of  a  Pump. — To  make  use  of  the  diagrams, 
let  us  assume  that  it  is  desired  to  pump  a  supply  of  300 
gallons  per  minute  from  a  well  in  which  water  stands  30 
feet  below  the  surface,  and  in  which  the  draw-down  will  not 


SECTION  THROUGH-  PLANE  OF 
!    IMPELLER,  VIEWING  FROM 
SUCTION  END 


SECTION  AT  A-B 

rCQ 


FIG.  22. — Cross-sections  of  4-inch  Pump,  Serial  No.  10.    (See  Diagram  10.) 

exceed  15  feet  at  this  discharge,  making  the  total  hydro- 
static head  at  this  discharge  about  45  feet.  In  the  follow- 
ing figure,  Fig.  23,  is  illustrated  the  meaning  of  the  terms 
relating  to  "head"  or  "lift." 


CENTRIFUGAL  PUMPS 


As  will  be  apparent  from  the  figure,  the  total  distance 
through  which  the  water  must  be  elevated,  or  the  hydro- 
static head,  is  the  distance  of  standing  water  below  the 
level  of  water  at  the  outlet,  plus  the  "draw-down";  and  the 


Pressure  Obs./8q.in.)  x  2.304=" 
Discharge  Head-Ft^A 

id-A+Bj£lfe 
= H  t-fri  ction^head  ±  h 
^difference  in  velocity  Bead  between 

discharge  anVsuction 
Suction  (inches  of  Mercury) xK133= 
action  HeadjFt.=B 


FIG.  23. 

total  head,  which  has  the  same  meaning  as  the  term  used 
in  the  pump  curve  diagrams,  is  the  hydrostatic  head,  plus 
the  friction  head,  plus  or  minus  a  small  correction  called  the 
difference  in  velocity  head.  The  hydrostatic  head  may  be 
determined  from  a  knowledge  of  the  depth  of  water  below 


88  PRACTICAL  IRRIGATION  AND  PUMPING 

the  surface  and  the  assumed  "draw-down,"  but  the  friction 
head  must  be  calculated  in  those  cases  where  it  cannot  be 
allowed  for  in  the  reading  of  a  pressure  gauge.  Thus  as 
shown  in  Fig.  23,  if  a  pressure  gauge  and  a  vacuum  gauge  be 
attached  to  a  pump  at  the  points  as  shown,  the  readings  of 
these  gauges,  multiplied  respectively  by  the  proper  con- 
stants as  indicated  in  figure,  give  the  total  head  in  feet, 
when  to  the  sum  is  added  the  vertical  distance  between  the 
centre  of  the  discharge  gauge  and  the  point  of  attachment  of 
the  vacuum  gauge  to  the  suction  pipe  (disregarding  the  cor- 
rection for  change  in  velocity  head).  Since,  however,  for 
a  pump  not  yet  installed,  the  gauge  readings  are  not  avail- 
able, the  total  head  must  be  calculated  by  adding  to  the 
hydrostatic  head  a  correction  for  the  friction  head.  It  is 
important  that  this  factor  be  allowed  for,  since  it  may  in 
unusual  cases  amount  to  as  much  as  the  hydrostatic  head. 
The  friction  head  may  be  denned,  for  the  benefit  of  those 
not  familiar  with  the  science  of  hydraulics,  as  that  head 
which  would  be  necessary  in  a  perfectly  level  pipe-line  to 
cause  a  flow  through  the  pipe  of  the  desired  quantity  of 
water.  Thus,  if  it  were  desirable  to  cause  a  flow  of  100 
gallons  per  minute  through  a  level  pipe  2  inches  in  diameter 
and  i oo  feet  long,  this  water  would  have  to  enter  the  pipe 
at  one  end  through  a  large  vertical  riser  at  least  22  feet 
high  in  order  that  such  discharge  might  occur.  In  other 
words,  the  friction  head  in  a  zoo-foot  length  of  pipe 
with  a  flow  of  100  gallons  per  minute  is  about  22  feet. 
It  is  seen  from  this  one  example  that  friction  head 
may  be  an  extremely  important  item  in  the  factors 
effecting  flow  of  water  in  pipes,  and  in  the  design  of 
pumping  plants  it  must  be  reduced  to  a  minimum,  as 
will  later  be  explained,  by  the  use  of  pipes  and  fittings 
of  proper  size,  in  order  that  the  cost  of  pumping  may 
be  reduced. 


CENTRIFUGAL  PUMPS 


89 


The  hydrostatic  head  in  the  instance  cited  on  page  86 
was  45  feet.  If  the  discharge  be  assumed  to  occur  at  the 
ground  surface,  the  vertical  length  of  pipe  involved  may 
be  assumed  to  be  the  same  as  the  hydrostatic  head,  and 
upon  this  assumption  for  the  general  case,  Diagram  12  is 
figured,  showing  for  various  capacities  and  depths  of  wells 


5 


100         200         300         400         500         600         700         800         900       1000 
Gallons  per  Minute 

DIAGRAM    12 

SIZES  OF  PIPE  SUITABLE  FOR  DIFFERENT  HEADS  AND  DISCHARGES 
BETWEEN  100  AND  1,000  GALLONS  PER  MINUTE 

up  to  a  total  hydrostatic  head  of  100  feet  the  commercial 
size  of  pipe  which  should  be  used  in  order  that  the  friction 
head  may  be  kept  below  a  certain  maximum.  In  using  the 
diagram  for  the  case  being  considered,  find  300  gallons 
per  minute  on  horizontal  scale  and  trace  vertically  upwards 
to  the  curve  marked  40  feet  hydrostatic  head. 

The  lift  in  the  present  case  is  45  feet,  but  since  we  can 
use  only  the  nearest  commercial  size,  which  as  seen  by  the 


9o 


PRACTICAL   IRRIGATION  AND   PUMPING 


scale  at  the  left  is  4-inch  pipe,  it  is  unnecessary  to  inter- 
polate. Hence,  provisionally  a  4-inch  pipe  for  the  discharge 
will  be  adopted.  Referring  now  to  Diagram  13  we  find 
a  means  of  determining  the  head  to  be  allowed  for 
friction. 

Following  vertically  upwards  from  300  gallons  per  min- 
ute, on  the  horizontal  scale  at  the  bottom,  to  the  curve 


100         200 


300 


700 


800 


900       1000 


400         500         601 
Gallons  per  Minute     - 

DIAGRAM    13 

FRICTION  HEADS  FOR  DIFFERENT  SIZES  OF  PIPE  100  FEET  LONG  DIS- 
CHARGING VARIOUS  QUANTITIES  OF  WATER 

marked  4-inch  pipe,  we  find  the  corresponding  friction 
head  for  loo-foot  length  of  pipe  is  about  6  feet.  For  an 
allowed  length  of  50  feet  in  this  case,  the  friction  head  will 
be  3  feet,  and  consequently  the  total  head  will  be  48  feet. 

An  examination  of  the  characteristics  of  various  pumps 
as  given  in  the  diagrams  (pages  77-83)  will  enable  us  to 
construct  the  following  table: 


CENTRIFUGAL  PUMPS 


91 


TABLE    VIII 

SPEEDS  AND  EFFICIENCIES  OF  VARIOUS  PUMPS  FOR  300  G.  P.  M.  AND 
48  FT.  TOTAL  HEAD,  AS  DERIVED  FROM  DIAGRAMS  OF 
PUMP  CHARACTERISTICS,  PAGES  77  TO  83 


Pump  No. 

Speed  R.  P.  M. 

Eff'y  % 

Size 
Discharge  Pipe 

I 

960 

48 

2^ 

3 

I,I2O 

45 

4 

7 

860 

27 

6 

8 

650 

35 

6 

10 

900 

53 

4 

ii 

560 

45 

4 

This  table  gives  two  criteria  which  may  be  used  as  a 
basis  of  selection:  first,  the  speed;  second,  the  efficiency. 
In  general,  it  may  be  said  that  a  slow-speed  pump  is  prefer- 
able, unless  it  is  to  be  driven  by  an  electric  motor  (in 
which  a  higher  speed  is  desirable,  particularly  in  direct- 
connected  sets),  because  of  the  longer  life  and  greater 
durability  of  bearings  of  the  slow-speed  machine.  From 
this  standpoint  it  would  appear  that  pump  No.  n  is 
preferable,  since  it  combines  a  very  moderate  speed  with 
reasonably  good  efficiency.  From  the  standpoint  of  effi- 
ciency, however,  it  is  evident  that  pump  No.  10  is  superior  to 
the  others,  particularly  since  the  speed,  900  R.P.M.,  is  by 
no  means  excessive.  In  case  fuel  cost  is  high,  No.  10 
should  be  chosen;  if  fuel  cost  or  power  cost  is  relatively 
unimportant,  choose  No.  n,  assuming  that  the  pumps 
themselves  sell  at  about  the  same  price.  Under  some  cir- 
cumstances it  may  be  desirable  to  operate  the  pump  for 
short  periods  at  a  greater  or  less  capacity  than  that  above 
given.  It  must  be  understood  that  this  is  a  poor  policy  in 
general,  for  it  will  usually  mean  a  very  considerable  lessening 
of  efficiency  unless  the  efficiency  curve  is  quite  flat  over  a 
considerable  range  of  speed.  The  relation  between  speed, 


PRACTICAL  IRRIGATION  AND  PUMPING 


horse-power  input,  and  efficiency  for  any  given  head  may 
readily  be  deduced  from  the  characteristic  curves  of  the 
pump  and  for  the  purpose  of  illustration  this  has  been  done 
for  pump  No.  10  when  working  at  48  feet  head.  The 
characteristic  curves  for  this  case  are  shown  in  Diagram  14. 
Although  the  total  head  will  vary  as  the  discharge  changes, 
due  to  change  in  frictional  head,  it  is  difficult  to  show  this 


1300 

1200       60 
g'llOO       50 

a 

llOOO   £  40      20 

r/j  fi 

a          -G 

|  900  §  30   1  15 

I 
800       20  £10 

700       10        5 


4  IN.  CENT.  PUMP 

SERIAL  NO.  10 

CHARACTERISTIC  CURVES  FOR 

48  FT.  TOTAL  HEAD 


X 


100         200          300         400         500 
Gallons  per  Minute 

DIAGRAM   14 


600 


on  a  diagram  and  consequently  Diagram  14  merely  shows 
how  a  change  in  speed  affects  efficiency,  horse-power  input, 
and  discharge  when  the  head  is  constant.  The  conditions 
represented  by  this  diagram  show  very  closely  what  actu- 
ally takes  place  when  a  pumping-plant  operator  for  any 
reason  changes  the  speed  of  his  engine  or  motor  or  alters 
the  ratio  of  driving  to  driven  pulleys.  As  may  be  seen  from 
the  diagram,  this  pump  will  deliver  300  G.P.M.  through 
48  feet  total  head  when  operated  at  a  speed  of  905  R.P.M. 


CENTRIFUGAL  PUMPS  93 

It  will  require  6.7  horse-power  delivered  at  the  pump  pulley 
to  accomplish  this  and  the  pump  will  have  an  efficiency  of 
about  52.5  per  cent.  This  is  not  the  highest  efficiency 
which  may  be  attained  by  this  pump,  but  it  is  that  at 
which  it  will  operate  when  fulfilling  nearest  the  required 
conditions.  Now  as  may  be  seen  from  Diagram  14,  the 
discharge  may  be  increased  to  double  the  amount,  or  to 
600  gallons  per  minute,  by  increasing  the  speed  to  about 
1,220  R.P.M.,  but  it  will  be  noted  that  the  efficiency  drops 
rapidly  so  that  at  this  speed  and  discharge  the  efficiency 
is  only  slightly  over  40  per  cent.,  the  horse-power  input  not 
being  proportional  to  the  discharge,  but  increasing  more 
rapidly  than  the  discharge  increases.  Consequently,  about 
20  per  cent,  more  fuel  will  be  used,  or  power  will  be  con- 
sumed, per  unit  of  water  pumped  at  the  higher  speed  than 
at  the  lower  speed,  and  it  would  evidently  be  unwise,  from 
the  standpoint  of  economy,  to  operate  the  pump  for  any 
length  of  time  under  these  conditions.  This  will  be  espe- 
cially true  in  case  an  electric  motor  is  used,  since  if  it  is 
rated  at  a  horse-power  corresponding  to  the  300  gallons 
per  minute  discharge,  it  will  be  seriously  overloaded  and 
will  heat  badly  at  the  higher  discharge,  if  indeed  it  can  be 
made  to  develop  the  greater  power  required,  belt  drive 
being  assumed  and  the  speed  change  being  secured  by 
change  in  pulley  ratio. 

Size  of  Engine  or  Motor 

The  foregoing  naturally  brings  up  the  question  of  the  size 
of  engine  or  motor  to  use.  For  convenience,  the  case  above 
given  will  be  considered  further.  As  may  be  seen  in  Dia- 
gram 14,  the  actual  horse-power  required  at  the  pulley  of  the 
pump  for  a  discharge  of  300  gallons  per  minute  against  48 
feet  total  head  is  6.7  horse-power.  Allowing  for  belt  slippage 
and  other  losses,  an  engine  or  motor  would  be  required 


94  PRACTICAL   IRRIGATION   AND   PUMPING 

rated  to  deliver  from  7  to  8  horse-power.  Although  in 
general  a  gasoline  engine  should  give  its  most  economical 
fuel  consumption  at  or  near  its  rated  power,  the  tendency 
of  most  engine  manufacturers  seems  to  be  to  over-rate 
gasoline  engines,  and  it  would  probably  be  better,  therefore, 
to  provide  an  engine  rated  at  9  to  10  horse-power.  This 
will  leave  a  slight  overload  capacity  available,  and  the 
engine  would  probably  be  found  to  govern  better  and 
work  more  reliably  than  would  the  engine  which  is  loaded 
up  to  its  rating.  With  an  engine  capable  of  delivering 
10  horse-power  it  would  be  possible,  as  may  be  seen  from 
the  curves  in  Diagram  14,  to  secure  400  G.P.M.,  approxi- 
mately, in  case  the  necessity  arose  and  provision  was  made 
for  changing  speed.  A  properly  designed  engine  or  motor 
will,  of  course,  have  a  definite  and  fairly  constant  speed, 
and  although  it  is  possible  to  change  this  speed  over  a 
slight  range,  the  engine-driving  pulley  and  the  pump  pulley 
should  be  so  selected  that  the  proper  pump  speed  will  result 
as  based  upon  the  mean  speed  of  the  engine  or  motor. 
Generally  the  size  of  the  pump  pulley  is  fixed,  and  cannot 
be  altered  because  of  the  design,  and  consequently  the 
size  of  the  engine  pulley  must  be  specified.  Ordinarily  it 
will  be  found  expedient  to  use  a  clutch  pulley  on  a  gasoline 
engine,  this  being  supplied  at  a  reasonable  price  as  an  extra 
by  the  engine  builders.  Let  it  be  assumed  that  an  engine 
of  the  size  contemplated  runs  at  a  speed  of  300  R.P.M. 
The  pump  in  question  is  to  have  a  speed  of  about  900  R.P.M. 
and  it  has  an  8-inch  pulley.  It  is  evident,  therefore,  that 

the  engine  clutch  pulley  should  be =  24"  diam- 
eter, and  this  size  should  be  specified  when  the  engine  is 
purchased.  Too  much  emphasis  cannot  be  placed  on  the 
proper  selection  of  engine  as  to  type  and  size  and  to  secur- 
ing the  proper  speed  for  the  pump,  since  the  economical 


CENTRIFUGAL  PUMPS 


95 


operation  of  the  plant  depends  upon  securing  the  highest 
efficiency  possible  from  the  pump  and  working  the  engine 
under  such  conditions  as  will  promote  the  use  of  a  minimum 
quantity  of  gasoline  per  unit  of  power  developed. 


Pump  Builders'  Diagrams 

The  above  desirable  conditions  of  operation  will  only 
be  secured  when  those   operating  pumping  plants  or  con- 


5"CENTRIFUGAU  PUMP 
CLASS  A 

CAPACITY-HEAD  AND  ISO-EFFICIENCY  D.IP.  CURVES 
CONSTANT  SPEED 


10 


§       I       I       i      §'     I       I       I.    §      1       § 

»-l         *-i        T->        rl        -pi 

Capacity  in  Gallons  per  Min. 
DIAGRAM   15 

templating  their  erection  give  their  attention  to  the 
characteristics  of  pumps  similar  to  those  described  and 
illustrated  in  the  preceding  pages  and  pump  builders  are 
willing  to  supply  authentic  curves  in  connection  with 


96  PRACTICAL  IRRIGATION  AND   PUMPING 

their  catalogues  similar  to  those  in  Diagrams  15-16-17. 
These  were  furnished  the  writer  through  the  courtesy  of 
one  of  the  largest  builders  of  pumping  machinery  in  the 
country,  and  are  particularly  valuable  in  the  light  they 
throw  upon  the  characteristics  of  the  various  sizes  of 
pumps  considered. 

The  use  of  these  diagrams  is  essentially  the  same  as 


CapaeUjjy  JQ  Gallons  perJlin. 
DIAGRAM  16 

those  already  described,  although  by  them  it  is  somewhat 
easier  to  interpolate  between  curves.  To  illustrate  the 
use  of  the  diagrams,  let  it  be  supposed  that  it  is  desired  to 
obtain  800  gallons  per  minute,  pumped  through  a  total 
head  of  70  feet.  The  questions  to  be  solved  are  (i),  the 
best  size  of  pump  to  use;  (2),  the  efficiency  at  which  it 
will  operate;  (3),  the  horse-power  necessary  to  be  pro- 


CENTRIFUGAL  PUMPS 


97 


vided;  (4),  the  speed  at  which  it  must  operate.  Let  it  be 
assumed  that  the  pump  is  to  be  operated  90  days  of  24 
hours  each  during  the  year  and  that  power  is  supplied  by 
an  electric  motor,  current  for  which  costs  2.8  cents  per 
K.W.  hour.* 

The  costs  of  the  three  pumps  whose  characteristics  are 


130 


4"CENTRIFUGAL  PUMP 
CLASS-A 


CAPACITY-HEAD  AND  ISO-EFFICIENCY-B.  H.P.  CURVES 
CONSTANT  SPEED 


100200300400500600700800900 
Capacity  in  Gal.  per  Min. 

DIAGRAM    17 

shown  in  the  diagrams  and  as  arranged  for  connection  to  an 
electric  motor  are: 

4-inch  pump $215.00  net  F.O.B.  cars  factory. 

5-inch  pump $255.00  net  F.O.B.  cars  factory. 

6-inch  pump $300.00  net  F.O.B.  cars  factory. 


*  The  cost  of  electric  power  is  frequently  fixed  by  a  sliding  scale 
so  that  there  is  a  certain  minimum  charge  whether  power  is  or  is  not 
used,  and  the  greater  the  amount  of  power  used  the  less  is  the  charge 
per  K.W.  hour.  (See  page  144.) 


98 


PRACTICAL  IRRIGATION  AND   PUMPING 


Referring  to  the  diagrams,  the  following  information  is 
given  as  shown  in  the  following  table: 

Table  showing  characteristics  of  three  pumps  delivering 
800  gallons  per  minute  through  7o-foot  total  head. 


Pump 

Speed 
R.  P.  M. 

Eff'y  % 

H.P. 
Required 

4" 

1,075 

41 

35 

5" 

785 

60+ 

23 

6" 

690 

62 

24 

Although  a  fairly  slow  speed  is  desirable,  none  of  the 
speeds  above  given  are  to  be  considered  excessive,  but, 
other  conditions  being  the  same,  the  6-inch  pump  would 
be  selected  from  this  standpoint  alone.  In  the  estimate  of 
depreciation,  however,  it  must  be  assumed  that  the  depre- 
ciation of  each  pump  increases  in  almost  direct  proportion 
to  its  speed.  Thus  letting  depreciation  on  the  6-inch  pump 
be  8  per  cent.,  on  the  5 -inch  pump  it  will  be  9.1  per  cent., 
on  the  4-inch  pump  12.5  per  cent.  Assuming  that  money 
commands  8  per  cent,  interest  and  that  the  yearly  length 
of  service  as  before  stated  is  90  days  of  24  hours  each,  we 
may  construct  the  following  table  giving  yearly  cost. 


Pump 

Motor 

Yearly 

Total 

Pump 

Interest  and 

Interest  and 

Cost  of 

Yearly 

Depreciation 

Depreciation 

Power 

Cost* 

4" 

$44-10 

$l6o.OO 

$2,820 

$3,024 

5" 

43.60 

I2O.OO 

1,850 

2,013 

6" 

48.00 

120.00 

1,935 

2,103 

*  Not  including  attendance  and  cost  of  lubrication,  or  interest  and 
depreciation  on  other  parts  of  plant  which  would  in  every  case  be  about 
equal. 


CENTRIFUGAL  PUMPS  99 

The  final  column  in  above  table  should  be  used  as  a 
basis  of  judgment  in  a  decision  as  to  size  of  pump,  since 
it  includes  interest  and  depreciation  on  the  plant  and  the 
cost  of  power.  It  is  also  evident  that,  since  the  4-inch  pump 
requires  a  larger  motor  because  of  the  greater  horse-power 
required,  it  will  be  more  expensive  in  first  cost.  It  is  evident 
that  the  5-inch  pump  is  the  one  which  should  be  selected 
for  the  assumed  conditions.  It  will  be  noted  that  yearly 
cost  of  power  in  above  example  is  really  the  decisive  factor, 
but,  as  may  readily  be  seen,  this  factor  will  decrease  in 
importance  as  the  number  of  days  of  the  year  during  which 
the  plant  is  operated  is  decreased.  The  foregoing  method 
of  selection  of  a  pump  is  suggested  as  being  advisable  when 
curves  similar  to  those  of  the  diagrams  are  available  and 
when  some  approximate  estimate  of  length  of  time  of 
pumping  and  cost  of  power  may  be  obtained. 

Pump  Equations 

An  examination  of  the  characteristic  curves  and  an  in- 
vestigation of  the  efficiencies  of  the  various  pumps  as  given 
in  the  preceding  pages,  must  lead  one  of  an  inquiring  mind 
to  wonder,  first,  why  an  average  of  50  per  cent,  of  the  work 
or  power  applied  to  pumps  of  the  types  tested  should  be 
lost  in  transforming  that  work  into  energy  of  flowing 
water,  and  second,  since  the  curves  showing  relation  between 
head  and  discharge  for  constant  speed  seem  to  follow  the 
same  law  for  all  pumps,  why  it  would  not  be  possible  to 
express  this  law  by  a  mathematical  expression  containing 
factors  which  properly  would  take  into  account  the 
peculiarities  and  proportions  of  the  pump.  To  the  solution 
of  the  first  question  the  present  investigation,  unfortu- 
nately, can  offer  no  clew  beyond  confirming  the  fact  that 
power  losses  are  unquestionably  (and  apparently  unnec- 
essarily) large  in  pumps  of  the  size  of  those  tested.  It 


IOO  PRACTICAL  IRRIGATION  AND  PUMPING 

would  seem  to  offer  a  very  fruitful  field  of  investigation  and 
experimentation,  particularly  on  the  part  of  manufacturers, 
to  devise  some  simple  shape  or  arrangement  of  impeller  and 
casing  to  do  away  with  the  losses  from  shock  and  friction 
which  now  accompany  the  change  from  velocity  head  to 
pressure  head  in  small  centrifugal  pumps.  And  experiments 
seem  to  show  that,  in  sizes  of  over  6  inches  and  in  a  few 
cases  of  that  size,  the  designs  of  some  manufacturers  have 
been  so  worked  out  that  efficiencies  of  75  per  cent,  and 
over  have  been  attained.  There  seems  to  be,  in  sizes  below 
6  inches,  the  opportunity  for  some  manufacturer  to  produce 
a  simple  centrifugal  pump  so  designed  that  it  will  equal  the 
efficiencies  attained  by  larger  sizes  and  yet  will  not  be  un- 
reasonably high  in  price. 

To  return  to  the  subject  of  loss  of  power  in  the  centrifugal 
pump,  it  may  be  said  that  it  undoubtedly  occurs  through 
a  combination  of  friction,  shock,  and  eddy  effects  in  all 
pumps,  and  to  the  eddy  effects,  etc.,  must  be  added  the 
leakage  through  clearance  spaces  in  the  more  poorly  de- 
signed and  built  pumps.  The  nature  of  these  losses,  how 
they  vary,  their  relative  or  absolute  amount,  and  the  best 
means  of  preventing  them,  all  remain  yet  to  be  discovered, 
and  the  subject  offers  a  most  engaging  field  to  investigators 
provided  with  the  requisite  equipment  and  resources. 

The  second  point  referred  to,  namely,  the  question  of 
rinding  some  expression  governing  the  relation  between 
discharge  and  head  at  constant  speed,  can  be  answered  to 
some  extent  by  a  consideration  of  the  theoretic  relations  in 
the  light  of  the  curves  given  and  the  proportions  of  the 
various  pumps. 

The  chief  factor  in  connection  with  the  theory  of  cen- 
trifugal pumps  is  the  head  or  vertical  distance  through 
which  the  water  may  be  pumped.  This  is  shown  by 
theory  to  be  directly  proportional  to  the  square  of  the 


CENTRIFUGAL T 

speed  of  the  impeller  or  rotating  part  of  the  pump.  The 
head  actually  realized  is  less  than  the  theoretical  by  the 
effect  of  water  friction  losses  in  the  passageways  surround- 
ing the  impeller  and  leading  to  the  pump  outlet,  and  in 
shock  or  impact  effects  at  entrance  to  and  upon  leaving 
the  impeller.  We  may  therefore  write: 

Actual  head  =  h  =  H  -  hi  -  h2  -  h3  -  h4 

=  theoretic  head— head  lost  in  friction,  etc. 
Where  h  =  actual  head  realized  in  feet. 
H  =  theoretic  head  in  feet, 
hi  =  head  lost  in  impeller. 
h2  =  head  lost  in  discharge  chamber. 
h3  =  head  lost  by  impact  at  entrance  to  impeller. 
h4  =  head  lost  by  impact  at  exit  from  impeller. 
Now,  as  is  well  known,  water  friction  losses  are  propor- 
tional to  the  square  of  the  velocity.    Hence: 

Let  S  =  velocity  of  water  passing  through  impeller. 
T  =f  velocity  of  water  in  discharge  chamber. 

Vi  =  velocity  of  outer  periphery  of  impeller. 
V2  =  velocity  of  inner  periphery  of  impeller. 
R  =  radial  velocity  of  water  at  entrance  to  impeller. 

Then  we  may  write: 
H  =  JVr> 

hi  =  M  S2 

h2  =  N  T2 

Where  J,  M,  and  N  are  constants  of  proportion. 

Impact  at  exit  from  impeller  may  be  considered  to  be 
proportional  to  some  quantity  P  Vi  (S  +  Vi),  since  it  is 
zero  when  Vi  is  zero,  it  increases  as  S  increases,  and  becomes 
merely  a  frictional  effect  proportional  to  Vi2  when  S  =  o. 
In  this  equation,  P  again  is  a  constant  of  proportion.  The 


IO2V  PiJ-keXlCAL  J&EIGATION   AND   PUMPING 

effect  of  impact  at  entrance  to  impeller  may  be  written  in 
a  similar  way,  since  at  impending  delivery  there  is  no  im- 
pact and  the  loss  at  entrance  to  impeller  is  then  a  frictional 
effect  which  during  discharge  must  be  proportional  to  the 
combined  effect  of  radial  and  peripheral  velocities.  Hence 
for  the  loss  of  head  at  entrance  to  the  impeller  we  may  write: 
h3  =  CV2(R  +  V2). 

But  since  R  is  proportional  to  S  and  since  V2  is  propor- 
tional to  Vi  we  may  write  h3  =  B  Vi  (S  +  Vi)  or  the  loss 
at  entrance  from  friction  and  impact  is  proportional  to 
the  loss  at  exit. 

Combining  various  terms  we  may  write: 

h  =JVi2-MS2-NT2-BVi  (S+Vi)-PVi  (S+Vi) 

Now  T  may  be  taken  as  proportional  to  Vi,  since  the 
water  in  the  discharge  chamber  evidently  rotates  at  some 
less  velocity  than  Vi  and  we  may  therefore  write  T2  = 
L  Vi2  where  L  is  a  constant. 

Expanding  and  substituting,  we  may  write: 

h=JV12-MS2-NLV12-BViS-BVi2-PViS-PVi2 

or 

h=  (J-NL-B-P)  Vi2-MS2-(B+P)  ViS. 
Let  (J-NL-B  -P)  =  K! 
Let  M  =  K2 

Let  B  +  P  =  K3 
and  we  have 

h  =  Ki  Vi2  -  K2  S2  -  K3  Vi  S 

as  representing  the  equation  for  the  actual  head  realized  by 
a  centrifugal  pump,  taking  into  account  losses  by  friction 
and  impact.  In  this  equation  S  may  be  represented  by  the 

term  —  where  Q  =  the  discharge  in  cubic  feet  per  second 
a 


CENTRIFUGAL  PUMPS  103 

and  a  =  the  total  area  of  water  passages  through  the  im- 
peller normal  to  the  flow  line  at  exit.    Hence: 


In  this  equation  the  constants  Ki,  K2,  and  K3  will 
evidently  be  applicable  to  only  one  type  and  size  of  pump, 
but  it  is  of  interest  to  determine  what  is  the  absolute  value 
of  such  constants  and  how  they  compare  for  different 
pumps.  To  determine  the  constants,  use  was  made  of  the 
method  of  least  squares,  which,  although  very  laborious,  is 
the  only  reliable  method  of  so  combining  a  series  of  obser- 
vations that  the  resulting  equation  will  be  the  best  possible 
average  of  all  the  observations.  The  method  was  applied 
to  the  head-discharge  curves  of  pumps  Nos.  1,3,  and  10, 
and  from  these  observations  the  following  equations  were 
derived: 

D2N2  Q2  DNQ 

Pump  No.  i,  h  =  .oo366--9.i5—  2-.oo9i^-cosa 


D2  N2  Q2  DNQ 

Pump  No.3,h  =  .oo3355        --9.31—  -.00947-^-  cosa 


D2N2  Q2  0  DNQ 

Pump  No.  io,h  =  .  00336  ---  2.740  -  —  .0208  --  cosa 

2g  y  2ga2  2ga 

It  will  be  noted  that  the  equations  have  been  slightly 
changed  from  the  general  form  above  given  and  that  a 
factor,  "cos  a"  has  been  inserted  in  the  last  member  to 
take  account  of  the  angle  of  the  vanes.  In  these  equations: 

D  =  Diameter  of  impeller  over  vane  tips  in  feet. 

N  =  Speed  of  impeller  in  R.P.M. 

2g  =  Twice  the  acceleration  due  to  gravity  =  64.4. 

The  agreement  of  these  equations,  or  the  curves  which 


104 


PRACTICAL  IRRIGATION  AND  PUMPING 


they  represent,  with  the  actual  curves  found  from  the  tests 
of  the  pumps  is  shown  in  Diagram  18. 

As  will  be  seen,  the  general  form  of  the  curve  given  by 
the  equation  seems  sufficiently  close  to  the  actual  curves  to 
warrant  the  belief  that  the  assumptions  upon  which  the 
original  equation  is  based  are  essentially  correct.  It  would, 
therefore,  be  possible  by  such  an  equation  to  predict  the 


Pump*  3 

Curves  from  Actual  Tests 
«          ««     Formulae         110 
.100 


0   100  200  300  400  500 
Gal.  per  Min. 


0    100  200  300  400  500  600    0 
Gal.  per  Min. 

DIAGRAM   18 


100  200  300  400  500  600 
Gal.  per  Min. 


performance  of  the  particular  pump  at  any  speed,  head,  or 
discharge  if  two  out  of  these  three  conditions  are  known. 
As  will  be  seen,  however,  the  correspondence  between  the 
constants  of  the  three  equations  is  not  sufficiently  close  to 
allow  the  equation  determined  for  one  pump  to  be  used  as 
a  basis  for  predicting  the  performance  of  another.  It  would 
seem,  therefore,  that  there  is  still  lacking  some  factor  de- 
pendent upon  the  size  or  proportions  of  the  pump  which 
must  be  used  in  the  original  equation  to  make  it  really 
general,  that  is,  applicable  to  any  series  of  pumps.  It  is 
thought,  however,  that  the  fact  that  an  equation  may  be 
made  to  apply,  within  a  reasonable  degree  of  accuracy,  to 


CENTRIFUGAL  PUMPS  105 

the  performance  of  even  one  pump  throughout  the  range 
of  working  conditions,  is  sufficiently  interesting  to  be 
worthy  of  notice. 

Locations  and  Conditions  Suitable  for 
Centrifugal  Pumps 

The  head  against  which  water  must  be  pumped  and 
the  capacity  desired  are  the  two  factors  which  largely 
decide  the  question  of  whether  a  centrifugal  pump  is  or  is 
not  suitable  in  irrigation  work.  So  far  as  their  construction 
is  concerned  it  is  now  possible  to  negotiate  almost  any 
lift  under  1,000  feet  and  the  maximum  quantity  which  can 
be  lifted  under  such  limitation  of  head  is  only  limited  by 
the  amount  of  power  available  and  the  difficulties  in  making 
large-sized  castings.  Centrifugal  pumps  are  in  successful 
operation  where  3,000  horse-power  is  absorbed  by  a  single 
unit,  but  such  an  example  has  no  bearing  upon  those  prob- 
lems connected  with  irrigation  from  wells  where  1,000 
gallons  per  minute  is  the  maximum  quantity  which  may  be 
developed  successfully  from  a  single  well  and  where  heads 
of  over  100  feet  belong  only  to  those  situations  where 
fruit  growing  make  such  lifts  profitable.  Where  the  supply 
is  pumped  from  an  open  water  source,  as  a  river  or  reser- 
voir, and  is  to  be  delivered  into  canals  or  distributaries, 
5,000-6,000  gallons  per  minute  have  been  handled  with 
success  in  a  single  unit,  but  at  comparatively  low  heads. 

In  general  it  may  be  said  to  be  feasible  to  use  centrif- 
ugal pumps  under  the  following  conditions: 

In  single  units — 

(1)  In  pumping  from  open  water  source  for  supply  of 
under  10,000  gallons  per  minute. 

(2)  In  pumping  from  wells  where  the  pump  may  be 
placed  not  over  5  feet  above  standing  water  level,  where 
total  depth  to  water  does  not  exceed  100  feet,  total  head 


II 

Ii 


•3 


a  M 
iJ  -s 
12 

-Si 


CENTRIFUGAL  PUMPS  1 07 

does  not  exceed  125  feet,  and  quantity  pumped  does  not 
exceed  1,000  gallons  per  minute. 

The  limitation  in  depth  in  (2)  arises  from  the  difficulty 
and  expense  of  sinking  a  pit  of  the  size  necessary  for  a  pump 
installation  to  a  depth  greater  than  100  feet.  The  limita- 
tion as  to  head  in  the  same  instance  arises  from  the  prac- 
tical difficulties  in  operation  inherent  in  centrifugal  pumps 
when  heads  as  much  or  greater  than  125  feet  are  encoun- 
tered. The  writer  bases  this  statement  upon  his  belief, 
based  upon  experience,  that  the  multi-stage  pump  used  in 
such  cases  is  not  free  yet  from  serious  objections  due  to 
end  thrust  and  internal  leakage,  the  first  due  to  high  pres- 
sure and  weight  of  shaft  in  case  of  vertical  pumps  and  the 
second  due  to  the  fact  that  well-water  is  likely  to  be  heavily 
charged  with  fine  sand  which  under  high  pressure  forces 
its  way  into  intermediate  bearings  and  stuffing  boxes  and 
quickly  causes  serious  wear  and  leakage.  Doubtless  means 
will  be  evolved  in  time  which  will  eliminate  these  difficulties, 
but  the  writer  has  yet  to  learn  of  a  centrifugal  pump  for 
these  conditions  in  which  the  design  has  been  so  far  per- 
fected that  when  operated  by  the  average  man  under 
practical  conditions,  the  difficulties  above  mentioned  will 
not  arise.  To  obviate  the  necessity  of  a  pump  pit  and  yet 
use  the  centrifugal  principle  in  very  deep  wells,  a  form  of 
centrifugal  multi-stage  pump  of  such  size  that  it  may  be 
lowered  inside  of  a  large  size  well-casing  has  been  put  on 
the  market  in  recent  years  and  under  favorable  conditions 
of  operation  has  given  much  satisfaction.  It  is,  however, 
an  expensive  type  of  pump  and  of  limited  capacity.  Its 
use  is  more  especially  recommended  for  water- works'  use, 
or  for  locations  where  water  has  acquired  a  high  value 
for  purposes  of  irrigation,  so  that  the  initial  expense  is 
justified.  See  Fig.  13,  page  65. 


CHAPTER  VIII 

DIFFERENT  TYPES   OF  INSTALLATION  FOR  CENTRIFUGAL 

PUMPS 

THE  head  to  be  pumped  against,  the  depth  to  water, 
and  the  character  of  power  to  be  used  are  determining  fac- 
tors in  the  decision  as  to  the  character  of  pump  and  general 
arrangement  of  plant,  and  every  plant  design  must  to  a 
certain  extent  be  based  upon  a  study  of  local  conditions. 
It  is  possible,  however,  to  give  a  few  examples  illustrating 
certain  types  of  installation  which  have  been  found  satis- 
factory in  practice  and  the  designer  may  then  vary  the 
details  to  suit  local  or  special  requirements. 

PLANT  No.  i 

The  plant  shown  in  Fig.  24  is  that  which  it  is  customary 
to  adopt  where  a  limited  quantity  of  water  is  to  be  lifted 
to  adjacent  high  lands  from  an  open  water  source.  (In  the 
case  shown  in  Fig.  24  this  is  supposed  to  be  a  canal.)  In 
such  a  case  the  pump  is  set  up  on  a  firm  foundation  at 
such  elevation  that  the  suction  is  not,  say,  over  10  feet 
vertically  above  the  lowest  water-surface  elevation  of  the 
source. 

The  design  shown  in  Fig.  24  may  be  modified  and 
materially  improved  by  providing  a  concrete-lined  sump 
or  pit  beneath  the  pump  house  with  a  passageway  leading 
to  the  canal.  In  this  passageway  grooves  should  be  left 
in  the  concrete  for  the  insertion  of  screens  or  trash  racks 
and  possibly  stop  planks  or  a  gate,  to  keep  water  out  of 
the  sump  in  an  emergency  or  for  cleaning.  This  scheme 

108 


INSTALLATION   FOR  CENTRIFUGAL  PUMPS  1 09 

also  allows  the  pump  and  motor  to  be  placed  further  away 
from  the  canal  on  a  more  secure  foundation  and  permits 
the  use  of  a  short  vertical  suction  pipe  which  is  a  very 
desirable  consideration.  In  some  cases  where  a  long 
discharge  pipe  is  necessary  to  reach  the  point  of  gravity 
distribution,  it  may,  according  to  the  nature  of  the  ground, 
be  cheaper  to  dig  a  supply  ditch  or  canal  some  distance 
inland  from  the  source  and  place  the  plant  closer  to  the 
point  of  discharge,  eliminating  more  or  less  expensive 
discharge  pipe,  and  possibly  enabling  a  smaller  size  to  be 
used. 

Friction  Effects. — It  must  be  remembered  that  the 
friction  effect  tends  to  increase  the  suction  lift  just  as  it 
does  the  lift  on  the  discharge  side  and  the  distance  from  the 
inlet  of  the  suction  pipe  to  the  inlet  of  the  pump  must 
not  be  great  enough  to  cause  a  friction  head  which  together 
with  the  vertical  suction  lift  will  much  exceed  25  feet,  which 
must  be  considered  the  economical  limit  of  suction  lift. 
Many  turns  and  valves  also  increase  the  friction  effect. 

Example. — An  example  will  probably  make  this  more 
clear.  Suppose  a  4-inch  pump  is  to  be  used.  This  size 
refers,  as  previously  explained,  to  the  diameter  of  the 
discharge  opening  of  the  pump.  The  suction  opening  is 
usually  at  least  one  size  larger  or  say  5  inches.  The  suc- 
tion pipe  should  in  no  case  be  less  than  the  size  of  the 
suction  opening  of  the  pump  and  if  the  suction  pipe  is  to 
be  of  considerable  length  it  should  be  at  least  two  sizes 
larger  than  the  nominal  size  of  the  pump.  Let  us  say  that 
in  this  case  5-inch  pipe  should  be  used  on  the  suction  line. 
Assume  that  the  pump  is  placed  10  feet  above  water  level 
and  that  the  distance  from  the  strainer  to  the  pump  is 
100  feet  measured  along  the  axis  of  the  pipe.  Also  assume 
that  there  is  a  foot-valve  on  the  strainer  and  two  elbows  in 
the  line.  If  the  pump  discharges  500  gallons  per  minute, 


110  PRACTICAL   IRRIGATION  AND   PUMPING 

the  friction  head  for  a  5-inch  pipe  of  the  length  assumed 
will  be  about  5.5  feet.  (See  Diagram  13.)  The  loss  of 
head  in  the  foot- valve  will  be  about  2.8  feet  and  in  the  two 
elbows  about  2  feet.  The  velocity  head  will  be  i  foot. 
The  total  suction  head  will  therefore  be  found  as  follows : 

Hydrostatic  head 10.00  ft. 

Loss  of  head  foot -valve  and  strainer 2.80 

Friction  head  in  100  ft.  5-inch  pipe 5.50 

Friction  head,  two  elbows 2.00 

Velocity  head i.oo 


Total  suction  head 21.30  ft. 

It  is  apparent  from  this  example  that  the  effect  of  friction 
in  a  long  suction  pipe  may  be  to  increase  the  suction  head 
by  more  than  double  the  actual  vertical  lift  and  for  this 
reason,  if  for  no  other,  it  is  advisable  to  have  a  suction  pipe 
as  short  and  direct  as  possible.  Of  course  the  use  of  a  large 
pipe  will  much  reduce  the  friction  head,  but  it  is  advisable, 
if  possible,  to  limit  the  length  of  the  suction  pipe  to  a  mini- 
mum from  the  standpoint  of  operation,  since  where  we  have 
a  long  and  crooked  pipe  we  also  have  many  joints  which  it 
is  always  difficult  to  keep  perfectly  tight,  as  they  must  be 
with  any  centrifugal  pump,  a  slight  air  leakage  into  the 
suction  cutting  down  the  flow  tremendously,  and  when 
serious  enough,  stopping  the  flow  entirely. 

Drive. — The  drive,  in  the  case  illustrated  by  the  figure,  is 
by  gasoline  engine,  though  steam  or  electric  power  could 
be  used  as  well.  It  is  advisable  to  use  a  generous  length  of 
belt  for  centrifugal-pump  drive,  the  distance  between  the 
engine  and  pump  centers  being  from  15  to  20  feet. 

Priming. — For  priming  the  centrifugal  a  common  pitcher 
pump  may  be  used.  This  should  be  connected  by  %-inch 
pipe  to  the  pipe  connection  to  be  found  on  the  top  of  the 
centrifugal  pump  casing.  An  ordinary  globe  valve,  or, 


INSTALLATION  FOR  CENTRIFUGAL  PUMPS      III 

what  is  better,  a  good  check  opening  outwards  should  be 
placed  in  this  line  and  after  the  priming  has  been  accom- 
plished the  operator  should  be  sure  that  no  air  leaks  into 
the  centrifugal  through  this  line.  If  the  pump  is  to  be 
primed  each  time  it  is  started,  a  check  valve  must  be  placed 
in  the  discharge  pipe  immediately  above  the  pump,  and  in 
any  case  where  the  pipe  discharges  into  a  tank  there  must 
certainly  be  provided  a  check  valve  to  prevent  the  emptying 
of  the  pipe  or  tank  when  the  pump  is  stopped.  If  no  check 
valve  is  used  the  priming  pump  is  useless  and  a  foot-valve 
at  the  strainer  is  necessary.  In  this  case,  to  prime  the 
pump  when  it  is  started  the  first  time,  the  plug  on  top  of 
pump  casing  must  be  removed  and  water  poured  in  through 
the  opening  till  the  suction  pipe  and  pump  are  full.  This 
presupposes,  of  course,  a  tight  foot-valve,  and  if  it  remains 
so  there  will  be  no  subsequent  necessity  for  priming. 
Foot-valves  are,  however,  subject  to  derangements,  and  af- 
ter a  stop  of  a  week  or  so  it  is  no  uncommon  experience  to 
find  that  all  the  water  has  leaked  back  through  the  foot- 
valve  and  the  tedious  process  of  priming  must  be  repeated. 
Ejector  Primer. — Where  a  check  valve  is  used,  the 
discharge  pipe  is  large  or  long  and  the  head  over  50  feet, 
thus  providing  a  considerable  supply  of  water  stored  at  the 
necessary  pressure,  a  very  convenient  method  of  priming 
is  by  the  use  of  a  water  ejector  attached  to  the  centrifugal 
similar  to  a  priming  pump  and  using  for  its  operation 
water  taken  through  a  small  pipe  connection  from  the 
discharge  pipe.  As  long  as  water  remains  in  this  pipe 
other  means  of  priming  will  not  have  to  be  resorted  to, 
but  must  be  provided  and  held  in  reserve.  For  power- 
driven  priming  pumps  the  use  of  a  small  water  pump  with 
a  discharge  pipe  carried  sufficiently  high  to  insure  that  the 
valves  will  always  be  immersed,  is  preferable  to  an  air-pump 
which  must  be  stopped  as  soon  as  the  centrifugal  is  primed 


112  PRACTICAL   IRRIGATION  AND   PUMPING 

to  prevent  damage  to  piston  and  valves  by  water  caught 
in  the  clearance. 

Discharge  Pipe. — The  same  statement  as  to  size  and 
alignment  of  pipe  from  the  standpoint  of  friction  applies 
to  the  discharge  as  to  the  suction.  A  small  pipe  with  many 
elbows  and  bends  causes  unnecessary  friction  losses,  and  it 
is  a  direct  saving  of  power  to  use  large  pipe  and  as  few 
elbows  as  possible. 

Water  Hammer. — An  important  matter  in  connection 
with  design  of  discharge  pipe  is  water  hammer.  When 
a  pump  is  suddenly  stopped,  as  in  the  case  of  a  motor- 
driven  unit  by  the  circuit  breaker  tripping,  there  is  a 
surging  back  and  forth  set  up  in  the  discharge  piping 
which  for  a  few  seconds  may  multiply  by  many  times  the 
usual  working  pressure.  If  a  check  valve  is  used  this 
excess  pressure  comes  upon  it  and  the  discharge  pipe,  but 
when  a  foot-valve  is  employed  the  hammer  effect  is  also 
expended  upon  the  pump  case  and  suction  pipe.  With 
very  long  discharge  pipes  and  heads  of  over  50  feet  some 
reliable  means  should  be  employed  to  relieve  excess  pressures. 
This  may  take  the  form  of  quick-acting  relief  valves  with 
a  free  water  passage  at  least  one-tenth  the  area  of  dis- 
charge pipe,  or  it  may  be  a  large  air  chamber  or  a  verti- 
cal surge  pipe  connected  to  the  discharge  above  the  check 
valve. 

Fittings. — Where,  as  is  illustrated,  the  water  is  to  be 
conveyed  to  a  point  immediately  above  and  adjacent  to 
the  plant,  it  will  be  found  an  economy  both  in  the  saving  of 
pipe  and  of  power,  through  lessened  friction  losses,  to  use 
45-degree  elbows  in  the  discharge  line.  "Long  Sweep"  fit- 
tings should  be  used  wherever  right-angle  turns  are  made 
either  in  suction  or  discharge  pipe,  and  if  stop  valves  are 
used  they  should  be  gate  valves  rather  than  globe  valves. 
The  use  of  the  latter  cannot  be  too  strongly  condemned  in 


INSTALLATION  FOR   CENTRIFUGAL  PUMPS 


FIG.  25. — A  common  type  of  plant  for  pumping  from  driven  well,  where  water  is 
found  at  shallow  depths. 


114  PRACTICAL  IRRIGATION  AND  PUMPING 

water-piping  in  general,  but  particularly  in  any  case  where 
economy  in  power  is  a  consideration,  since  it  is  to  be  re- 
membered that  a  globe  valve  causes  the  same  friction  head 
as  would  be  caused  by  100  feet  of  the  same  nominal  size 
of  pipe. 

Pump. — As  to  the  type  of  pump  to  use  for  a  plant  such 
as  is  illustrated  in  Fig.  24,  there  is  no  question  as  to  the 
eminent  desirability  of  a  horizontal  centrifugal.  If  the  total 
head  is  less  than  70  to  100  feet  the  single-stage  pump  should 
be  used,  but  for  greater  heads  the  necessary  speed  of  the 
single-stage  pump  will  be  excessive  for  successful  and  long- 
continued  operation  and  a  multiple  stage  should  be  used. 
Where  electrical  power  is  available  at  reasonable  cost  a 
pump  direct  connected  to  a  motor  will  be  found  most  con- 
venient. If  a  gasoline  engine  is  used,  it  should  be  selected 
of  a  make  known  to  be  reliable.  Some  suggestions  on  this 
point  will  be  found  in  Chapter  XIII. 

PLANT  No.  2 

The  pumping  plant  shown  in  Fig.  25  is  of  a  type  very 
common  in  those  sections  of  the  West  where  water  is 
found  at  shallow  depths,  as  in  river  valleys  immediately 
adjacent  to  streams,  and  water  is  pumped  either  to 
supplement  a  gravity  supply  or  is  used  by  some  fruit  or 
truck  grower  for  an  independent  and  dependable  water 
supply. 

Pump  Pit  and  Arrangement  of  Belt  Drive. — In  such  a 
plant  an  open  pit  6  to  8  feet  square  or  round  is  first  dug 
to  water  and  lined  with  timber  or  in  some  cases  with  con- 
crete. Owing  to  the  use  in  this  case  of  an  inclined  belt 
reaching  from  the  engine  at  the  surface  to  the  horizontal 
centrifugal  pump  in  the  pit,  such  pits  are  limited  to  a  depth 
of  about  25  feet.  With  greater  depths  it  is  not  feasible  to 


INSTALLATION  FOR   CENTRIFUGAL  PUMPS  115 

use  the  inclined  belt,  owing  to  its  excessive  length.  It 
might  be  suggested  that  in  order  still  to  use  the  horizontal 
pump  with  deeper  pits,  a  counter-shaft  could  be  placed 
across  the  top  of  the  pit  from  which  a  vertical  belt  might 
extend  to  the  pump.  This  has,  however,  a  serious  disad- 
vantage in  the  use  of  the  vertical  belt,  which  seldom  works 
satisfactorily,  besides  which  there  is  a  loss  of  power  in  the 
use  of  the  countershaft  and  two  belts  instead  of  one.  With 
the  inclined  belt,  the  sag  of  the  belt  increases  the  arc  of 
contact  on  the  driving  and  driven  pulleys  and  the  weight 
of  the  belt  gives  the  necessary  adhesion  to  the  pulleys 
without  the  excessive  initial  tension  necessary  for  a  vertical 
belt.  Rope  transmission  has  been  suggested  (and  used  in 
a  few  instances),  for  deep  pits  where  it  was  desired  to  use 
a  horizontal  centrifugal  pump,  but  the  complication  and 
expense  of  this  form  of  power  transmission  do  not  recom- 
mend it  for  irrigation  work. 

Since  for  reasons  just  given  this  type  of  plant  is  limited 
to  locations  where  water  is  found  not  deeper  than  25  feet 
below  the  surface,  it  may  be  possible  in  firm  ground  to  dig 
the  pit  without  lining  same  as  excavation  proceeds,  but  as 
soon  as  the  pit  and  belt  chute  have  been  completed,  the 
lining  should  be  put  in  without  delay.  For  a  really  perma- 
nent structure  and  where  the  expense  is  not  prohibitive,  a 
4-  to  6-inch  concrete  lining  should  by  all  means  be  provided 
and,  in  case  concrete  is  used,  it  will  be  found  more  economi- 
cal in  excavation  and  in  use  of  concrete  and  but  little  more 
expensive  in  forms  to  make  the  pit  circular.  The  inside 
diameter  should  not  be  less  than  6  feet  and  the  same  mini- 
mum dimensions  hold  for  a  square  or  rectangular  pit.  In 
most  cases  a  wooden  lining  will  be  used  which  under  aver- 
age conditions  should  last  seven  to  ten  years  before  it 
needs  renewing.  A  common  practice  in  building  a  wooden 
lining  is  to  use  2"  x  6"  or  2"  x  8"  vertical  sheathing  inside 


Il6  PRACTICAL  IRRIGATION  AND   PUMPING 

of  which  a  4"  x  6"  horizontal  framing  is  spaced  every  4 
feet  vertically. 

Well  Pipe  and  Strainer. — The  pit  having  been  lined, 
the  next  thing  in  order  is  the  sinking  of  the  well-tube,  a  job 
which  should  be  left  to  the  professional  well-driller,  but 
which  may  be  negotiated  by  the  layman  if  he  has  the 
necessary  tools  and  the  large  amount  of  patience  required, 
together  with  considerable  ingenuity.  The  matter  of  well 
sinking  has  been  considered  in  Chapter  V.  If  the  top  of 
the  strainer  is  from  22  to  25  feet  below  the  level  of  ground 
water,  the  suction  connection  of  the  pump  can  be  made 
directly  to  the  top  of  the  well-pipe,  but  in  case  of  a  shallow 
water-bearing  formation  or  where  for  any  reason  the  top 
of  the  strainer  is  less  than  22  feet  below  the  level  of  standing 
water,  then  a  suction  pipe  or  draft  tube  should  be  dropped 
down  inside  the  well-pipe  and  strainer  to  at  least  25  feet 
below  standing-water  level  and  the  pump  connected  to 
this  suction  pipe. 

Pump  Foundation. — No  floor  is  required  usually  in  a 
well-pit,  but  the  pump  should  rest  on  heavy  timbers 
attached  to  the  pit  lining,  since  the  material  for  some  dis- 
tance around  the  well-pipe  is  apt  to  settle  considerably 
soon  after  pumping  begins,  particularly  if  much  sand  is 
removed,  and  unless  the  pump  is  securely  supported  inde- 
pendently of  the  floor,  it  is  likely  to  settle  out  of  align- 
ment, not  only  making  it  difficult  to  run  the  belt  properly, 
but  possibly  cracking  a  suction  flange  connection. 

Fittings. — The  connection  at  the  top  of  the  well-pipe 
or  draft  tube  should  be  a  tee  capped  with  a  blind  flange, 
rather  than  an  elbow,  since  in  case  there  is  considerable 
fine  sand  around  the  strainer  it  is  likely  to  accumulate 
inside  the  strainer  and  considerably  reduce  the  capacity  of 
the  well.  With  a  tee  connection  on  the  suction  pipe  it  is 
a  very  easy  matter  to  remove  the  blind  flange,  lower  a 


INSTALLATION  FOR   CENTRIFUGAL  PUMPS  1 17 

sand  bucket,  and  bail  out  the  sand.  In  general,  it  will  be 
found  that  it  is  decidedly  more  convenient  to  use  flanged 
instead  of  screw  fittings  in  all  pipe  work  in  the  pit,  due  to 
the  narrow  quarters  in  which  work  must  be  done  and  the 
difficulty  of  using  large  pipe  wrenches  in  making  up  screwed 
connections. 

Immediately  above  the  pump  a  check  valve  should  be 
placed  in  the  discharge  line,  since,  there  being  no  possibility 
of  using  a  foot- valve  in  a  driven  well,  a  priming  pump  must 
be  used  each  time  the  pump  is  started,  to  fill  the  centrifugal 
with  water.  In  some  cases,  flap  valves  are  used  on  the  end 
of  the  discharge  pipe  and  we  have  seen  some  small  plants 
provided  with  nothing  better  than  a  large,  tapered  plug 
covered  with  a  piece  of  rubber  belting,  which  was  driven 
into  the  end  of  the  discharge  pipe  to  make  an  air-tight  end. 
The  disadvantage  in  this,  aside  from  its  crudeness,  is  that 
air  in  the  long  discharge  pipe  must  be  partially  exhausted 
by  hand  pumping  before  water  will  rise  into  the  centrif- 
ugal pump  to  such  an  extent  that  it  will  prime  itself  and 
establish  the  flow.  A  check  valve,  suitable  for  the  use 
named,  may  be  purchased  at  a  reasonable  figure  in  any 
size  desired  from  any  machinery  or  well-supply  house,  and 
is  a  justifiable  expense.  This  valve  should,  if  possible,  be 
of  the  "increaser"  type,  that  is,  one  end  should  have  a 
flange  connection  the  same  as  the  flange  on  the  pump,  but 
the  other  end  should  be  provided  with  flange  for  the  next 
larger  pipe  size,  since  in  all  but  the  shallowest  wells  and 
lowest  lifts  the  discharge  pipe  should  be  a  size  larger  than 
the  outlet  of  the  pump,  in  order  to  decrease  the  friction 
head. 

It  is  also  the  part  of  wisdom  to  attach  a  vacuum  gauge 
to  the  suction  pipe  near  the  pump.  This  may  be  done  by 
boring  and  tapping  out  a  hole  for  a  J^-inch  pipe  connection. 
The  hole  should  be  bored  on  the  horizontal  axis  of  the  pipe 


Il8  PRACTICAL   IRRIGATION  AND   PUMPING 

near  the  suction  flange  of  the  pump.  The  vacuum  gauge 
will  indicate  the  "  draw-down,"  and  will  show  whether  the 
strainer  is  open  and  in  good  condition,  and  whether  the 
underground  supply  is  holding  out.  In  case  the  strainer  is 
not  clogged,  a  gradual  increase  in  the  reading  of  the  vacuum 
gauge  will  indicate  that  the  supply  is  failing  and  that  the 
ground-water  level  is  being  lowered  by  pumping  or  other 
causes.  A  sudden  increase  in  the  " draw-down"  usually 
indicates  a  clogging  of  the  strainer  by  sand  or  other  material, 
and  is  a  condition  requiring  immediate  attention. 

Drive. — Little  need  be  said  here  regarding  the  belt  drive, 
since  it  is  a  very  simple  matter  where  a  chute,  as  indicated, 
is  used.  Figure  25,  illustrating  such  a  plant,  shows  a 
gasoline  engine  drive,  but  steam  engine  or  motor  drive 
might  be  substituted,  if  conditions  warranted  and  it  was 
not  desirable  to  use  a  direct-connected  plant,  such  as  is 
indicated  in  Fig.  26. 

PLANT  No.  3 

This  plant  is  similar  in  every  way  to  that  just  discussed, 
except  that  the  pump  is  direct  connected  to  a  motor  mounted 
upon  the  same  bed-plate.  This  is  not  recommended  where 
the  pit  is  likely  to  be  very  damp,  or  where  there  is  a  possi- 
bility at  any  time  of  the  ground  water  rising  to  such  an 
extent  as  to  submerge  the  pump  and  motor.  The  depth  of 
the  pit  in  this  case  is  limited  merely  by  the  fact  that  a  pit 
rather  large  in  dimensions  is  needed  and  consequently  the 
limiting  depth  for  the  direct-connected  pump  may  probably 
be  placed  at  about  50  feet. 

Advantages. — This  type  of  plant  has  many  advantages 
from  the  standpoint  of  convenience  over  an  engine-driven 
plant,  and  is  what  might  be  termed  a  standard  type  for 
central  station  systems  of  pumping  where  electric  power  is 


INSTALLATION  FOR   CENTRIFUGAL  PUMPS  1 19 


FIG.  26. — An  electric-driven  plant  for  pumping  from  depths  within  50  feet.    A  stand- 
ard type  of  installation  for  the  individual  plants  in  a  central  station  project. 


I2O  PRACTICAL   IRRIGATION  AND   PUMPING 

generated  at  some  central  point,  and  distributed  over  a 
considerable  area  to  numerous  individual  plants  of  the 
type  described.  The  power  being  alternating  current  of 
standard  frequency  and  voltage  in  all  cases,  the  motor  is 
of  the  induction  squirrel-cage  type,  and  is  practically 
fool-proof. 

Pump  and  Motor  Speeds. — It  is  of  very  great  importance 
in  direct-connected  sets  to  have  the  pump  so  built  or 
selected  that  at  the  motor  speed,  which  is  practically 
unchangeable,  the  greatest  efficiency  will  be  realized 
from  the  pump  for  the  particular  conditions  of  head 
and  discharge  that  prevail  at  the  given  plant.  Unfor- 
tunately, since  stock  pumps  are  used  in  these  installa- 
tions, and  the  motor  speed  will  vary  between  900  and 
1,700  R.P.M.  according  to  size  and  type,  it  only  now 
and  then  happens  that  a  pump  is  running  at  the  speed 
at  which  it  should  run  for  the  total  head  prevailing 
if  a  minimum  current  consumption  is  desired.  By  the 
use  of  characteristic  curves  as  described  in  Chapter  VII, 
this  situation  might  be  changed  by  choosing  a  pump 
which  at  the  motor  speed,  the  head,  and  discharge  desired, 
would  give  a  maximum  efficiency.  Lack  of  attention 
to  this  matter  has  discouraged  several  plant  operators 
known  to  the  writer,  who,  in  paying  excessive  bills  for 
electric  current,  were  unknowingly  paying  for  their  lack  of 
knowledge  of  the  characteristics  of  a  centrifugal  pump. 
They  were  finally  forced  to  abandon  the  use  of  electric  drive 
in  favor  of  gasoline  engine  or  steam  where  inefficient  plant 
operation  does  not  so  quickly  make  itself  felt  or  noticed  as 
is  the  case  where  one  can  see  the  dollars  slipping  away 
with  every  unnecessary  revolution  of  the  index  of  the 
watt-hour  meter. 

Wiring. — In  the  installation  of  an  electric  plant  all 
wiring  should  be  put  in  by  an  experienced  electrician,  and 


INSTALLATION  FOR   CENTRIFUGAL  PUMPS  121 

the  wires  should  be  laid  in  conduits  both  in  the  pump 
house  over  the  pit  and  in  the  pit  itself  down  to  the  motor. 

Attention  Required. — If  the  priming  pump  is  at  the  sur- 
face, as  is  possible  where  the  pumping  set  is  not  over  25 
feet  below  the  surface,  about  all  the  attention  required  of 
the  operator  besides  seeing  that  the  pump  is  oiled  (and  this 
may  be  done  from,  the  surface,  if  desired),  is  to  operate  the 
hand  pump  until  the  centrifugal  is  primed  and  then  by 
starting  box  to  start  the  motor.  No  attention  should  be 
required  by  the  plant  during  an  eight-  or  ten-hour  run,  at 
the  end  of  which  time,  of  course,  re-oiling  is  necessary. 

Electric  Drive  the  Ideal  Arrangement. — Electricity  very 
closely  approaches  the  ideal  power  for  irrigation  pumping, 
and  unless  the  local  rates  for  current  are  excessive,  it  will 
pay  one  to  consider  its  adoption  very  closely  before  deciding 
upon  steam,  producer-gas,  gasoline,  or  distillate  drive, 
since  with  these  the  expense  for  attendance  is  a  consider- 
able item  in  the  total  cost  of  pumping,  but  it  is  almost  en- 
tirely obviated  with  electric  drive.  With  some  of  the  best 
gasoline  engines,  attendance  may  be  a  very  small  expense, 
but  the  writer  has  yet  to  learn  of  any  gas-engine-driven 
plant  in  which  the  operator  could  leave  it  entirely  to  itself 
during  an  8-  or  lo-hour  day,  thus  being  free  to  give  his 
entire  attention  to  the  distribution  of  the  water. 

PLANT  No.  4 

This,  as  shown  by  Fig.  27,  is  introduced  to  show  a 
design  similar  to  that  used  on  one  of  the  largest  low-lift 
central  station  pumping  plants  in  the  West,  in  which  water 
is  pumped  from  a  river  and  distributed  over  a  large  acreage 
by  means  of  concrete-lined  canals  and  ditches.  As  shown 
by  the  figure,  A  is  the  centrifugal  pump  of  very  large  size, 
driven  by  an  induction  motor,  B.  There  may  be,  and  in 
the  instance  cited,  are,  several  such  sets  in  one  pump-house. 


122 


PRACTICAL   IRRIGATION   AND   PUMPING 


INSTALLATION   FOR   CENTRIFUGAL  PUMPS  123 

The  drive  is  by  a  silent  chain,  C,  which  enables  a  relatively 
short  distance  between  shaft  centres  to  be  used.  E  is  the 
priming  pump,  and  F  is  the  valve  in  the  discharge  line  used 
when  priming  the  centrifugal.  L  is  a  strainer  set  in  a  block 
of  concrete,  and  D  is  the  starting  box.  It  will  be  noted  that 
practically  the  entire  lift  in  this  case  is  suction  lift.  In 
pumps  of  this  size,  relatively  high  efficiencies  were  attained 
in  tests  by  the  builders  of  the  pump  and  are  probably  con- 
stantly maintained  so  long  as  operating  conditions  remain 
the  same  as  those  for  which  the  pumps  were  designed.  In 
some  cases,  indeed,  pumps  in  use  some  time  show  better 
efficiencies  than  new  ones,  owing,  doubtless,  to  the  lessened 
water  friction  as  the  cored-out  passages  become  smoother 
under  the  scouring  action  of  the  water. 

Direct-connected  units  would  probably  be  preferable 
to  chain  drive  if  the  proper  motor  speed  could  be  secured. 

Applications  of  the  Low-Lift  Plant. — The  type  of  plant 
illustrated  by  Fig.  27  is,  of  course,  of  limited  application, 
since  it  is  seldom  that  conditions  are  found  similar  to  those 
for  which  this  plant  was  designed.  It  may,  however,  in 
exceptional  cases,  be  found  cheaper  to  build  a  pumping 
plant  rather  than  a  gravity  system,  owing  to  slight  river 
slope  which  makes  a  long  canal  necessary  in  order  to  reach 
the  lands  to  be  irrigated,  or  unfavorable  conditions  for  a 
headgate,  such  as  a  shifting  river  bed,  floods,  etc.,  may 
sometimes  justify  the  building  of  a  pumping  plant  at  some 
point  adjacent  to  the  lands  to  be  irrigated.  When  either 
water-power  or  cheap  coal  is  available,  a  careful  study  of 
relative  costs  may  show  a  decided  advantage  in  favor  of  a 
pumping  plant  similar  in  type  to  that  shown  in  Fig.  27. 

PLANT  No.  5 

When  the  depth  to  standing  water  exceeds  25  feet,  and 
for  any  reason  an  electrically-driven  plant,  as  shown  in 


124  PRACTICAL   IRRIGATION  AND   PUMPING 

Fig.  26,  is  inadvisable  or  impossible,  it  is  customary  to 
adopt  the  vertical  centrifugal  pump,  which  is  driven  by  a 
shaft  extending  from  the  surface. 

Suspension  Frame. — The  pump  itself  is  suspended  in  a 
framework  of  wood  or  steel,  which  is  held  at  the  surface  by 
a  trussed  frame  resting  on  the  top  of  the  curbing.  By  this 
method  of  suspension,  the  pump  is  kept  in  true  alignment 
with  the  shaft  and  no  difficulties  are  encountered,  due  to 
the  sinking  or  displacement  of  the  pump,  as  might  occur  if 
the  pump  were  supported  independently  of  the  frame  on  a 
foundation  built  in  the  bottom  of  the  pit.  The  framework 
is  always  provided  with  cross  and  diagonal  bracing  on  a 
6-  or  y-foot  spacing,  and  the  cross-braces  support  self- 
aligning  bearings  for  the  vertical  shaft,  see  Fig.  30. 

Step  Bearing  and  End  Thrust. — At  the  surface  is 
usually  a  cast-iron  frame  provided  with  ample  bear- 
ings, to  take  the  side  thrust  due  to  the  pull  of  the  belt,  and 
a  step  bearing  at  the  top,  which  takes  the  weight  of  the 
entire  shaft,  pulley,  and  impeller,  and  any  unbalanced  end 
thrust  due  to  the  action  of  the  pump.  This  bearing  is  the 
most  important  bearing  in  the  entire  installation,  and  is 
the  one  which,  if  poorly  made,  is  apt  to  give  more  trouble 
than  all  the  rest  of  the  installation  combined.  In  some 
makes  of  pump,  the  end  thrust  due  to  the  action  of  the 
pump  is  supposed  to  balance  the  weight  of  the  shaft  pulley 
and  impeller,  and  elaborate  means  are  provided  to  accom- 
plish this  end.  Usually,  however,  it  is  found  that  such 
schemes  are  more  or  less  of  a  failure,  since  a  slight  change 
in  operating  conditions,  such  as  speed  or  head,  cause  an 
unbalancing  of  the  system  and  the  necessity  for  re-adjust- 
ment. In  other  pumps  no  attempt  is  made  to  balance  the 
weight  of  the  shafting  pulley  or  impeller,  the  hydraulic 
end-thrust  being  eliminated  by  the  construction  of  the 
pump,  and  the  weight  of  the  rotating  parts  is  taken  up  by 


INSTALLATION  FOR  CENTRIFUGAL  PUMPS      125 

ball  or  roller  bearings  in  a  well-designed  step  bearing. 
When  well  made,  this  latter  type  is  likely  to  prove  the  more 
satisfactory  under  the  conditions  of  irrigation  work,  al- 
though under  stable  operating  conditions  there  is  likely  to 
be  less  mechanical  friction  loss  and  consequently  a 
higher  efficiency  attained  with  the  balanced  step 
type. 

Stages. — The  number  of  "steps"  or  stages  to  adopt  for 
the  pump  will  depend  upon  the  head.  If  the  discharge  is  to 
occur  at  the  surface  and  ground  water  is  encountered  at 
less  than  50  feet  below  the  surface,  the  single-step  or  single- 
stage  pump  may  be  used  satisfactorily,  but  for  greater  dis- 
tances below  the  surface  a  two-stage,  or  multi-stage 
pump  should  be  used.  Although  there  is  no  reason  why 
greater  depths  should  not  be  negotiated  (as  indeed  have 
been  in  various  parts  of  the  West),  the  limiting  depth 
for  really  satisfactory  operation  of  this  type  of  plant  may 
be  said  to  be  reached  when  the  pit  reaches  a  depth  of  75  or 
80  feet.  Vertical  shafts  longer  than  this  increase,  rapidly, 
the  difficulties  of  operation,  and  for  greater  depths  it  will 
be  advisable  to  use  either  electric  drive  with  a  vertical  or 
horizontal  direct-connected  motor-driven  pump  or  some 
other  type,  as  will  be  noted  later. 

Priming. — For  gasoline  or  electric  drive,  hand  priming 
is  necessary,  unless  a  small  electric-driven  air-pump  aux- 
iliary can  be  afforded.  If  a  hand  pump  be  used  for  exhaust- 
ing air  from  the  centrifugal,  it  must  be  located  at  the 
bottom  of  the  shaft,  for  it  will  be  found  practically  impos- 
sible to  make  joints  in  a  line  reaching  to  the  surface  suf- 
ficiently tight  to  enable  the  pump  for  priming  to  be  placed 
there.  With  steam-driven  plants,  a  24-inch  or  i-inch  steam 
line  may  be  extended  down  into  the  pit  to  operate  an  ejector, 
which  if  used  with  a  check  valve  between  the  ejector  and 
pump,  will  obviate  the  necessity  of  going  down  into  the  pit 


126 


PRACTICAL   IRRIGATION  AND   PUMPING 


at  all  for  priming,  since  the  steam  may  be  admitted  into 
the  priming  line  by  a  valve  at  the  surface. 

Discharge  Pipe  and  Details. — The  same  remarks  as  to 
well-pipe  connections,  valves,  and  discharge  pipe  apply  to 
this  plant  as  to  those  previously  considered.  A  large-sized 
discharge  pipe  should  be  used  and  long  radius  tees  and 
elbows  rather  than  common  fittings. 

Driving  Pulley. — The  pulley  at  the  top  of  the  vertical 
shaft  should  be  so  placed  that  a  horizontal  plane  through 
the  crown  of  the  pulley  will  be  about  on  a  level,  possibly 


FIG.  29. 


a  little  above,  the  centre  of  engine  pulley,  when  this 
pulley  rotates,  as  shown  in  Fig.  28.  When  the  centres  of 
the  driving  and  driven  pulleys  are  from  1 6  to  20  feet  apart, 
as  they  should  be  in  such  case,  the  weight  of  the  belt  and 


INSTALLATION   FOR   CENTRIFUGAL  PUMPS  127 

the  pull  of  the  tight  side  will  cause  it  to  lower  on  the  ver- 
tical pulley  as  far  as  the  tension  will  allow.  It  not  infre- 
quently happens  that  the  vertical  pulley  has  to  be  re- 
adjusted in  position  after  the  plant  is  put  in  operation  and 
sometimes  it  will  be  found  necessary  to  use  an  idler  for 
this  type  of  drive,  but  its  use  should  be  avoided  if  possible. 
It  should  when  used  be  placed  not  less  than  3  feet  from  the 
vertical  pulley,  and  the  highest  part  of  its  circumference 
should  be  placed  on  a  level  with  the  centre  of  the  vertical 
pulley.  In  a  vertical  plane,  that  side  of  the  circumference 
of  the  vertical  pulley  from  which  the  belt  leaves,  should  be 
tangent  to  a  plane  passing  through  the  crown  of  the  driving 
pulley  of  the  motor  or  engine. 

When  the  driving  pulley  rotates  as  in  Fig.  29,  a  hori- 
zontal plane  through  the  crown  of  the  vertical,  or  driven, 
pulley  should  pass  tangent  to  or  below  lowest  portion  of 
circumference  of  driving  pulley.  The  same  condition  with 
respect  to  the  vertical  position  of  the  vertical  pulley  holds 
as  in  the  former  case. 

PLANT  No.  6 

Vertical  Electric  Drive. — Where  electric  power  is  avail- 
able, a  very  satisfactory  type  of  centrifugal  plant  fulfilling 
the  same  purpose  as  stated  for  Plant  No.  5  is  shown  in 
Fig.  30.  The  underground  portion  of  this  plant  is  in  all 
respects  similar  to  the  one  last  described,  but  the  drive  is 
by  an  electric  motor  mounted  vertically  on  a  framework  at 
the  surface,  and  connected  to  the  vertical  shaft  by  a  flexible 
coupling.  A  vertical  thrust  bearing  takes  the  weight  of  shaft 
and  couplings  and  the  motor  is  self-contained,  the  weight  of 
the  revolving  armature  being  taken  up  by  a  thrust  bearing 
in  the  motor  itself.  Such  a  plant  put  out  by  an  experienced 
and  reliable  manufacturer,  although  expensive,  has  many 


128 


PRACTICAL  IRRIGATION  AND   PUMPING 


FIG.  30. — A  type  of  installation  for  deep  well  pumping  using  multi-stage  centri- 
fugal pump  in  open  pit. 


INSTALLATION   FOR   CENTRIFUGAL  PUMPS  1 29 

advantages  in  point  of  durability  and  convenience  over 
the  type  of  drive  illustrated  in  Fig.  28,  there  being  no  belt- 
ing or  idlers  and  the  power  being  instantly  available.  This 
plant,  like  the  one  preceding,  is,  in  the  judgment  of  the 
writer,  limited  to  pits  not  much  exceeding  75  feet  in  depth. 

MEANS   OF   WATER  MEASUREMENT 

In  connection  with  an  irrigation  pumping  plant,  the  im- 
portance of  providing  some  means  of  measuring  the  dis- 
charge can  scarcely  be  sufficiently  emphasized,  especially 
when  centrifugal  pumps  are  used.  It  enables  a  constant 
check  to  be  made  upon  the  performance  of  the  plant, 
indicating  when  the  pumps  are  falling  off  in  efficiency  or 
becoming  clogged,  or,  in  the  case  of  the  driven  well  plant, 
may  indicate  a  fouling  of  the  strainer  or  increase  of  draw- 
down. It  enables  efficiency  tests  to  be  made  upon  com- 
pletion of  plant,  and  facilitates  such  tests  at  intervals 
during  its  life  to  determine  if  efficiency  is  being  maintained. 
The  plans  for  a  plant  should,  if  possible,  therefore,  always 
provide  some  accurate  means  of  measurement  of  pump  dis- 
charge. This  generally  takes  the  form  of  a  trapezoidal  weir 
at  or  near  the  discharge  outlet,  though,  if  the  slight  increase 
in  head  thus  caused  is  objectionable,  a  rating  flume  might 
be  used.  In  some  cases,  a  Venturi  tube  may  offer  the  only 
feasible  solution,  as  where  the  water  is  distributed  over 
the  area  irrigated  in  underground  conduits. 


CHAPTER  IX 

TYPICAL  PLANTS  NOT  USING   CENTRIFUGAL  PUMPS 

WHEN  the  depth  to  water  is  from  75  to  100  feet,  the 
multi-stage  centrifugal  pump,  while  not  at  all  impractica- 
ble, becomes  increasingly  difficult  to  operate,  satisfactorily, 
in  the  hands  of  the  average  man  who  is  not  a  mechanical 
expert  or  without  long  experience  in  this  work. 

The  Question  of  Sand. — It  must  be  understood,  of 
course,  that  where  much  sand  is  apt  to  be  pumped  with  the 
water,  as  is  always  the  case  when  the  strainer  is  landed  in  a 
body  of  water-bearing  sand,  the  only  economically  feasible 
method  of  pumping  is  by  the  centrifugal  pump.  The  air 
lift  need  not  be  considered  in  this  connection,  due  to  its 
well-known  lack  of  economy.  In  case  the  sand  problem 
does  not  enter  in,  then  it  may  be  well  to  adopt  the  type  of 
plant  shown  in  Fig.  31. 

Duplex  and  Triplex  Pumps. — In  this  case  we  employ  a 
duplex  or  triplex  pump  with  the  working  head  at  the  sur- 
face and  the  pump  cylinders  in  a  pit  a  short  distance  above 
the  level  of  standing  water.  The  pump  plungers  are  oper- 
ated by  rods  extending  between  the  pump  cylinders  and 
the  working  head,  the  rods  being  held  in  vertical  alignment 
by  roller  guides  attached  to  timbers  extending  across  the  pit 
at  points  spaced  from  5  feet  to  6  feet  apart  vertically. 

Drive. — The  working  head  may  be  driven  by  a  steam 
or  gasoline  engine,  but,  where  electric  current  is  available, 
may  be  actuated  by  a  motor  connected  either  through 
gears  or  a  silent  chain  belt. 

Capacity  Limited. — The  capacity  of  such  a  pumping  set 
is  limited,  since  the  number  of  strokes  per  minute  cannot 

130 


TYPICAL  PLANTS   NOT   USING   CENTRIFUGAL  PUMPS    131 


FIG.  31. — Showing  use  of  triplex  reciprocating  pump  in  deep  pit. 

exceed  a  certain  maximum,  owing  to  inertia  effects.  With 
a  given  size  of  cylinders,  the  capacity  of  the  pump  will 
be  the  volume  displaced  per  minute  by  the  two  or 
three  cylinders  multiplied  by  a  certain  correction  factor 
for  slip  which,  in  a  well-designed  pump  in  good  condition, 
should  not  be  less  than  85  per  cent.,  that  is,  the  amount  of 
water  lost  by  slip  should  not  exceed  15  per  cent.  Such 
pumps  are  made  in  sizes  having  piston  displacement  of 


132  PEACTICAL   IRRIGATION   AND   PUMPING 

from  50  to  300  gallons  per  minute  at  40  working  strokes  per 
minute.  These  pumps  for  irrigation  work  should  be  pro- 
vided with  leather-packed  pistons  and  rubber  valves,  since 
when  so  equipped  they  are  less  likely  to  be  injured  by  sand. 
Brass-lined  cylinders,  although  better  in  other  ways,  are 
likely  to  be  more  quickly  scarred  and  ruined  by  sand  than 
are  those  less  expensive.  The  suction  and  discharge  piping 
should  be  installed  according  to  suggestion  already  given 
for  other  plants. 

Advantages  and  Efficiency. — This  type  of  pump  has 
the  evident  advantage  over  a  centrifugal  in  requiring  no 
priming,  it  can  be  used  in  a  pit  of  a  little  smaller  dimen- 
sions, the  difficulties  attendant  upon  the  use  of  long  vertical 
shafting  are  absent,  and  finally,  the  mechanical  efficiency  is 
somewhat  higher  than  in  most  centrifugal  pumps  and 
should  in  a  well-designed  and  installed  plant  amount  to 
between  70  and  80  per  cent.,  figuring  between  the  power 
input  to  the  working  head,  and  the  energy  of  the  moving 
water. 

Vertical  Rods. — The  vertical  rods  must  be  in  perfect 
alignment  for  satisfactory  operation,  and  the  pump  cylin- 
ders must  be  very  securely  anchored,  since  the  alternate 
pull  of  the  rods  in  a  deep  pit  is  a  very  severe  stress  which 
must  be  resisted  by  the  anchor  bolts  holding  down  the 
cylinders.  In  a  plant  of  this  type  installed  by  the  writer, 
the  cylinders  were  bolted  to  a  very  heavy  timber  bedded 
horizontally  in  the  concrete  wall  of  the  pit. 

Deep  Well  Pumps 

The  limit  of  open-pit  construction  may  be  said  to  be 
reached  at  a  depth  of  100  feet,  and  if  an  irrigation  supply 
is  to  be  obtained  from  depths  greater  than  this,  it  is  prob- 
able that  a  study  of  the  problem  will  limit  the  solution  to 


TYPICAL   PLANTS   NOT   USING   CENTRIFUGAL   PUMPS   133 

the  use  of  some  type  of  deep- well  apparatus,  i.e.,  a  pump 
cylinder  in  a  driven  well  with  a  pumping  head  at  the  sur- 
face, or  in  exceptional  cases  a  deep-well  turbine  pump  might 
be  recommended,  although  this  is  limited  to  wells  of  large 
bore  and  is  expensive  equipment. 

Deep- well  apparatus,  either  in  the  single  and  familiar 
single-acting  pump  cylinder  or  in  the  more  complicated 
double-acting  cylinders,  and  with  various  valves,  etc.,  are 
made  by  a  considerable  number  of  makers,  and  competi- 
tion in  this  line  has  developed  a  type  of  machinery  which 
in  the  better  grades  affords  a  striking  evidence  of  the 
attention  now  paid  to  details.  In  the  pump  heads  we  now 
find  such  details  as  white  metal  bearings,  oiling  systems, 
drop  forgings,  massive  and  well-braced  frames,  and  so  on, 
where  formerly  it  was  simply  put  together  to  be  sold 
rather  than  to  run. 

Capacity  Limited. — Deep-well  pumps  are  not  particu- 
larly desirable  for  irrigation  work  (aside  from  the  fact 
that  deep-well  pumping  is  expensive)  since  the  quantity  of 
water  developed  by  such  pumps  is  usually  far  below  the 
most  modest  requirements  and  the  flow  of  many  days' 
pumping  must  be  stored  in  a  reservoir  in  order  to  provide  for 
one  day's  irrigation.  The  capacity  of  such  pumps  depends 
upon  the  diameter  of  pump  cylinder,  the  length  of  the 
stroke,  the  number  of  strokes  per  minute,  and  the  slip. 

Speed. — In  general,  the  number  of  double  strokes  or,  in 
other  words,  the  revolutions  of  the  crank,  should  not  exceed 
40  per  minute,  and  for  extreme  depths  probably  not  more 
than  25,  in  order  that  the  stresses  due  to  the  reciprocation 
of  the  long  sucker  rod  and  heavy  plunger,  and  the  inertia 
of  the  water  column  may  not  be  excessive. 

Drive. — Where  electric  power  is  available,  the  most  sat- 
isfactory drive  is  a  motor  mounted  on  the  same  base  as  the 
pumping  head,  and  geared  to  it  by  a  rawhide  or  cloth  pinion. 


134  PRACTICAL   IRRIGATION  AND   PUMPING 

Belt  drive  from  a  steam  or  gas  engine  is  equally  satisfactory 
in  case  electric  power  is  not  available,  and  in  this  case  it  is 
advisable  in  selecting  a  pumping  head  to  choose  one  in  which 
the  belt  wheel  is  mounted  as  low  as  possible. 

Important  Details. — If  a  pumping  head  is  desired  in 
which  there  shall  be  freedom  from  annoying  and  costly 
breakdowns,  attention  should  be  paid  to  the  selection  of  a 
pumping  head  which  is  massively  built,  in  which  there  are 
substantial  guides  and  a  babbitted  cross-head,  all  bearings 
should  be  babbitt-  or  brass-lined  and  those  machines  should 
be  given  preference  which  do  not  have  overhanging  bear- 
ings, and  in  which  the  gear  teeth  are  cut  rather  than  cast. 
Such  attention  to  details  of  construction  will  mean  very 
much  more  reliable  machines,  and  one  in  which  stoppages 
for  hot  boxes  and  repairs  will  be  much  less  frequent,  although 
of  course  the  first  cost  of  the  machine  is  going  to  be  higher 
than  the  machine  in  which  not  so  much  attention  is  paid 
to  the  refinements  mentioned. 

With  this  type  of  plant,  the  capacity  is  so  relatively 
small,  even  in  the  largest  sizes,  that  it  will  be  found  that  a 
reservoir  is  an  absolute  essential  to  its  successful  use  in 
irrigation. 


CHAPTER  X 

COST  OF  PUMPING 

Importance   of   Knowledge   of   Pumping   Costs. — The 

matter  which  most  immediately  interests,  or  should  inter- 
est, the  man  who  expects  to  take  up  the  practice  of  irrigation 
by  pumping,  is  that  of  cost,  and  it  is  upon  this  point  par- 
ticularly that  he  should  take  special  pains  to  become  thor- 
oughly and  reliably  informed.  There  are,  unfortunately, 
too  many  projects  now  in  the  West  which  probably  would 
never  have  been  carried  through  had  the  owners  been 
careful  to  acquaint  themselves  beforehand  with  reliable 
information  from  unprejudiced  sources  on  the  various 
details  of  cost. 

Plant  Owners'  Statements  Unreliable. — It  might  be 
said  at  this  point  that  the  prospective  pumping-plant  owner 
will  do  well  to  accept  with  some  reservations  the  statements 
of  the  owners  of  existing  plants,  both  as  to  the  cost  of  oper- 
ation and  the  capacity  of  their  plants.  Since  many,  if  not 
most,  of  such  plants  are  the  product  of  the  owner's  labor 
and  thought,  he  is  bound  to  have  a  certain  pride  in  his 
achievement  which  blinds  him  to  its  faults  and  leads  him 
to  entertain  a  possibly  sincere  conviction  that  his  only 
pumping  expense  or  charge  is  for  power,  that  he  uses  less  of 
this  as  compared  with  the  amount  of  water  pumped  than 
any  of  his  neighbors,  and  usually  also  makes  him,  when  in 
public,  estimate  the  capacity  of  his  plant  at  just  about 
double  what  an  actual  measurement  will  show  it  to  be. 
There  has  long  been  a  need  for  some  authoritative  tests 
to  determine  the  actual  cost  of  pumping  and  although  a 

135 


136  PRACTICAL  IRRIGATION  AND  PUMPING 

beginning  has  been  made  in  the  matter  by  several  investi- 
gators, including  the  writer,  there  yet  remains  much  to  be 
done  before  reasonably  reliable  estimates  are  possible  for  a 
given  set  of  conditions. 

Factors  Affecting  Cost  of  Pumping. — The  cost  of  pump- 
ing depends  upon  the  following  factors: 

(1)  Cost  of  Power,  which  involves — 

(a)  The  quantity  of  water  pumped. 

(b)  The  total  head  through  which  this  quantity 

is  pumped. 

(c)  Efficiency  of  pump. 

(d)  Efficiency  of  transmission  of  power  between 

engine  or  motor  and  pump. 

(e)  Cost  of  steam,  gasoline,  distillates,  or  elec- 

tricity. 

(2)  Interest  on  first  cost  of  plant,  and  depreciation. 

(3)  Maintenance  and  repairs. 

(4)  Attendance. 

These  several  items,  numbered  i,  2,  3,  4,  enter  into  the 
cost  accounts  of  any  enterprise  involving  power  or  manu- 
facturing a  product  by  the  use  of  power,  and  should,  there- 
fore, enter  into  the  calculations  of  the  man  who  proposes  to 
run  a  pumping  plant  on  a  businesslike  basis.  In  order  that 
each  may  be  properly  understood,  the  items  will  be  discussed 
in  order. 

(i)   Cost  of  Power 

Head  and  Quantity  Pumped  Determine  Power  Require- 
ment.— A  pump  running  steadily  raises  a  certain  quantity 
of  water  through  a  certain  distance  every  minute.  Since 
each  gallon  weighs  about  8K  pounds,  the  pump  lifts  a 
certain  weight  every  minute  through  a  certain  height,  and 
consequently  performs  work  just  as  does  a  laborer  in  a 


COST   OF   PUMPING  137 

trench  who  elevates  to  the  surface  every  minute  or  two  a 
shovelful  of  dirt  weighing  a  certain  amount.  Now,  in  the 
case  of  the  laborer,  if  he  throws  out  larger  shovelfuls  at  the 
same  intervals  of  time  as  before,  and  from  the  same  depth, 
he  is  doing  more  work  than  before,  as  is  he,  also,  if  he  con- 
tinues to  throw  out  the  same  sized  shovelfuls  in  the  same 
intervals  of  time,  but  from  a  greater  depth.  This  illustrates 
the  two  facts  frequently  ignored  by  pump  operators,  first, 
that  if  the  quantity  of  water  discharged  per  minute  is  in- 
creased when  the  head  remains  the  same,  the  amount  of 
work  done  by  the  pump  increases  in  direct  proportion; 
second,  that  if  the  quantity  is  not  changed,  but  the  head 
increased,  the  work  will  be  increased  in  direct  proportion. 
From  this  it  follows  that  the  work  done  by  the  pump  varies 
as  the  product  of  head  times  discharge.  Consequently,  it 
will  require  twice  as  much  power  and  the  power  cost  will  be 
double  for  a  5o-foot  head  what  it  would  be  for  a  25-foot 
head  for  the  same  quantity  of  water  pumped.  It  is  of  con- 
siderable importance,  therefore,  that  prospective  pumping- 
plant  operators  realize  fully  the  fact  that  the  attempt  to 
pump  against  a  high  head  jeopardizes  their  chances  of  suc- 
cess, since  power  used  up  in  overcoming  head,  represents  an 
outlay  for  which  there  is  no  return,  whereas  power  used  in 
increasing  the  discharge  results  in  greater  acreage  irrigated 
and  greater  profits.  It  being  seen,  therefore,  that  head  and 
capacity  are  the  two  factors  governing  the  amount  of  power 
required,  it  is  of  importance  to  calculate  or  estimate  closely 
the  probable  requirement  of  the  specific  design  in  question. 
The  method  of  estimating  the  power  requirement  is  given 
in  Chapter  VII,  page  86. 

The  power  required  being  known,  it  is  then  in  order  to 
estimate  the  cost  of  power.  This  will  depend,  in  turn,  upon 
the  type  of  engine  adopted,  for  it  may  be  said  that  that 
engine  will  or  should  be  used,  which  under  the  local  con- 


138  PRACTICAL  IRRIGATION  AND  PUMPING 

ditions  will  give  power  most  cheaply.  Without  going  into 
the  mechanical  details  of  the  machines,  which  will  be  dis- 
cussed elsewhere,  it  may  be  said  that  a  choice  must  be  made 
from  the  following: 

(1)  Steam  Engines, 

(2)  Gasoline  Engines, 

(3)  Crude  Oil  or  Distillate  Engines, 

(4)  Producer  Gas  Engines, 

(5)  Electric  Motors. 

The  cost  of  power  will  now  be  discussed  for  each  of  the 
several  prime  movers  mentioned,  as  based  upon  informa- 
tion from  tests  made  by  the  writer,  and  as  drawn  from 
sources  known  to  be  authoritative,  as  well  as  conservative. 

Steam. — The  cost  of  power  developed  in  a  steam  plant 
varies  considerably  with  the  size  of  the  plant.  This  follows 
from  the  fact  that  the  smaller  the  plant  the  greater  in  pro- 
portion are  the  heat  losses,  due  not  only  to  lack  of  refinement 
in  the  details  of  the  equipment,  but  also  to  certain  physical 
laws  which  it  is  unnecessary  to  discuss  here.  The  cost  of 
power  in  a  steam  plant  may  be  said  to  depend  wholly  upon 
the  amount  of  coal  used,  since,  under  most  circumstances, 
the  boiler  feed  water  is  a  minor  expense,  and  may  be  neg- 
lected. In  all  centrifugal-pump  plants  an  automatic,  simple 
or  compound  engine  should  be  used,  since  the  rotative  speed 
of  the  pump  being  high  the  engine  speed  may  also  be  high. 
Corliss  type  engines  are  practically  eliminated  from  con- 
sideration in  connection  with  the  size  of  plants  which  it  is 
the  purpose  of  the  author  to  treat.  For  very  large  plants, 
such  as  used  in  the  rice  belt,  Corliss  engines  are  probably 
economically  justifiable.  The  steam  consumption  of  the 
automatic  high-speed  engine  will  vary  from  a  minimum  of 
30  pounds  delivered  horse-power  per  hour  in  the  larger 
engines  to  50  or  60  pounds  in  the  smaller  sizes.  The  amount 


COST   OF  PUMPING 


of  coal  required  per  delivered  horse-power  hour  of  engine 
and  boiler  feed  pumps  will  depend  not  only  upon  the  size  of 
engine,  but  also  upon  the  size  and  type  of  boiler.  In  the 
smaller  plants  the  amount  of  coal  burned  per  delivered 
horse-power  per  hour  of  engine  will  vary  from  a  maximum 
of  nearly  15  pounds  in  the  small  plants,  to  an  average  of  8 
or  9  pounds  in  the  larger  plants  below  200  horse-power. 

The  following  diagram  shows  for  different  sizes  of  plants 
and  different  prices  of  coal,   the  fuel  cost  per  delivered 


100 
90 
80 

|TO 

^60 

W50 

r 

30 
20 
10 

HOURLY  FUEL  COST 

HIGH  SPEED  STEAM  ENGINES 
AUTQMATIC-NON-CONDENSING 

II 

1 

/ 

H 

1 

/ 

" 

# 

/ 

7 

*/ 

7 

& 

c 

/ 

c 

f 

/ 

/ 

/ 

/ 

10      20      30      40      50      60      70      80      90     100 
Fuel  Cost-  Cents  per  Hr. 

DIAGRAM    19 

horse-power  hour  and  the  fuel  cost  per  hour  of  operation. 
For  plants  operated  but  ten  hours  per  day,  about  10  per 
cent,  should  be  added  to  the  values  given  by  the  diagram 
for  the  standby  losses. 

This  diagram  shows  the  basis  upon  which  a  reasonably 
safe  estimate  of  the  cost  of  power  may  be  based  in  steam 
plants  of  sizes  within  the  limits  given  by  the  diagram.  To 
illustrate  use  of  diagram,  suppose  that  it  is  found,  for  a 


140 


PRACTICAL   IRRIGATION   AND   PUMPING 


given  set  of  conditions,  that  an  engine  capable  of  deliver- 
ing 70  horse-power  is  desired.  Following  horizontally  across 
to  the  curve  representing  the  price  of  coal,  the  cost  per  hour 
in  dollars  is  found  vertically  beneath  on  the  horizon- 
tal scale.  The  cost  per  hour  for  coal  at  prices  different 
from  those  of  the  diagram  may  be  obtained  by  direct 
proportion. 

Gasoline. — The  gasoline  engine  is  most  useful  in  pump- 
ing plants  requiring  less  than  30  horse-power.     At  and 


HOURLY  FUEL  COST 
GASOLINE  ENGINES 

/ 

I 

/ 

1 

/ 

^ 

/ 

a 

^' 

/ 

$ 

/ 

•q 

^ 

• 

? 

c 

f 

f 

/—£ 

>1 

^ 

e> 

x£ 

" 

- 

X 

10      20      30      .40      50      60      70      80      90     100 
Fuel  Cost  -Cents  per  Hr. 

DIAGRAM   20 

below  that  power,  it  makes  the  most  convenient  and  cheap, 
if  not  always  the  most  reliable  power  we  have.  In  the  hit- 
and-miss  governed  gasoline  engines,  the  full-load  fuel  con- 
sumption for  an  engine  in  good  order  varies  between  about 
i  pint  of  fuel  per  delivered  horse-power  per  hour  in  the  large 
engines,  to  about  double  that  amount  in  the  smallest.  The 


COST  OF  PUMPING  141 

power  cost  per  hour  is  shown  graphically  in  Diagram  20  for 
gasoline  costing  16  and  24  cents  per  gallon. 

Crude  Oil  and  Distillates. — Crude  oil  has  not  come  into 
use  for  engines  of  small  power,  say  below  10  to  15  horse- 
power, and  its  combustion  is  attended  by  difficulties  of  so 
serious  a  nature  that  it  can  only  be  used  in  engines  of 
special  type  which  are  very  much  more  expensive  per  horse- 
power than  ordinary  internal-combustion  engines.  Crude 
oil  from  the  California  fields  is  difficult,  if  not  impossible, 
to  use  in  such  engines  without  previous  distillation,  owing 
to  its  heavy  asphaltum  base,  but  oils  from  the  Texas 
and  Louisiana  fields  may  be  and  are  being  used  with  fair 
success. 

Distillates,  that  is,  oils  from  which  the  lighter  hydro- 
carbons, such  as  gasoline  and  engine  naphthas,  etc., 
have  been  distilled  off,  and  the  heavy  bases  removed 
are  very  commonly  used  both  in  special  engines  and  in 
engines  of  the  ordinary  type  fitted  with  special  carbu- 
retors. Kerosene  is  rapidly  taking  the  place  of  gasoline 
in  localities  where  gasoline  is  expensive,  but  kerosene, 
like  other  lower-grade  distillates,  cannot  be  used  in  gaso- 
line carburetors.  The  tremendous  growth  in  the  demand 
for  gasoline  for  use  in  pleasure  and  commercial  auto- 
mobiles, to  say  nothing  of  the  great  number  of  farm 
engines,  tractors,  etc.,  and  its  uses  in  the  industries,  is 
doubtless  responsible  for  a  rapid  increase  in  its  price,  so 
that  unless  the  condition  is  relieved,  it  will  soon  have  a  very 
serious  effect  upon  the  fuel-cost  factor  in  pumping.  One 
attempt  to  meet  the  situation  has  resulted  in  the  evolution 
of  a  new  fuel  known  as  "Motor  Spirit,"  which  is  said  to  be 
a  combination  of  gasoline  and  kerosene  and  which  sells  at  a 
few  cents  under  the  market  price  of  gasoline.  This  fuel  is 
claimed  to  have  a  higher  heating  value  per  pound  than 
gasoline  and  to  have  no  objectionable  qualities  as  an  engine 


142  PRACTICAL   IRRIGATION   AND   PUMPING 

fuel  except  a  rather  pungent  odor  from  the  exhaust.  The 
introduction  of  this  fuel  is  not  thought,  however,  to  have  any 
very  deterrent  effect  upon  the  rise  in  price  of  fuel  oils  in 
general. 

Distillates  could,  until  recently,  be  purchased  at  the 
refineries  at  about  2^  cents  per  gallon  F.O.B.  in  tank-car 
lots  and  rarely  cost  more  than  4  cents  per  gallon  at  the 
nearest  railroad  point  in  tank-car  quantities.  The  recent 
advances  in  crude  oil  have,  however,  somewhat  increased 
these  prices.  Since  a  gallon  of  distillate  weighs  about  7 
pounds,  it  follows  that  i  pound  of  distillate  at  4  cents  per 
gallon  costs  0.57  cents.  The  fuel  consumption  of  an  oil 
engine  is  usually  stated  in  pounds  of  fuel  oil  per  delivered 
horse-power  per  hour  rather  than  in  pints  or  gallons,  owing 
to  the  variable  weight  of  oil  per  gallon.  The  makers  of  the 
Hornsby-Akroyd  type  of  engine  in  this  country  guarantee  a 
fuel  consumption  at  full  load  of  i  pound  per  delivered  horse- 
power per  hour.  A  test  of  a  17 -horse-power  engine  of  an 
engine  of  this  type  at  near  full  load,  made  by  the  writer, 
gave  a  fuel  consumption  of  i.io  pounds  Solar  oil  per 
delivered  horse-power  per  hour.  This  engine  was  used  for 
driving  a  centrifugal  pump.  It  probably  is  wise  to  count 
on  a  fuel  cost  of  from  0.6  cent  to  0.7  cent  per  delivered  horse- 
power per  hour  for  such  fuel  in  an  engine  specially  designed 
to  use  it,  with  oil  at  4  cents  per  gallon.  For  oil  at  greater  or 
less  price  per  gallon  than  that  mentioned  the  price  per 
horse-power  hour  would  vary  accordingly.  Crude  oil 
engines  of  the  high  pressure  or  Diesel  types,  when  in  first- 
class  condition,  will  operate  on  from  0.50  to  0.75  pounds 
crude  oil  per  hour,  but  such  engines  in  this  country 
are  not  made  in  small  sizes,  i.e.,  less  than  about  125 
horse-power. 

Producer  Gas. — Undoubtedly  the  cheapest  power  on 
earth  to-day  is  producer  gas  when  made  in  an  efficient  pro- 


COST   OF   PUMPING 


143 


ducer  and  used  in  an  efficient  engine.  There  is  no  question 
whatever  but  that  in  the  gas  producer  lies  the  solution  of 
the  smoke  nuisance  and  the  problem  of  producing  power 
cheaply  from  coal.  In  the  course  of  time,  when  engines 
and  gas-producing  processes  have  become  more  perfected, 
it  is  doubtful  if  the  steam  engine  will  be  used  in  any  enter- 
prise where  we  have  continuous  operation.  In  other  cases, 
also,  the  gas  producer  will  be  used  when  producer-gas  equip- 
ment is  so  far  reduced  in  price  as  compared  with  steam 
equipment  of  equivalent  power  that  the  fuel  saved  by  the 
producer  will  more  than  equal  the  difference  in  the  fixed 
charges  on  the  two  types  of  plants.  Producer  gas  may  be 
made  from  a  great  variety  of  materials,  among  which  are 
anthracite  coal,  charcoal,  coke,  bituminous  coal,  lignite, 
oak  bark,  sawmill  refuse,  or  wood  of  various  kinds.  Of  these, 
the  first  three  named  are  the  most  commonly  and  success- 
fully used,  and  those  alone,  indeed,  which  it  is  possible  to 
use  satisfactorily  in  the  ordinary  suction  producer.  Al- 
though producers  for  bituminous  or  soft  coal  have  been 
devised  for  commercial  use,  they  are  much  more  compli- 
cated, and  therefore  considerably  more  costly,  than  the 
hard-coal  producer.  Unfortunately,  anthracite  similar  to 
that  of  Pennsylvania  is  unknown  in  the  Western  States, 
except  by  importation,  and  its  use  is,  therefore,  out  of  the 
question,  since  it  sells  for  from  $6  to  $12  or  $15  per  ton, 
depending  upon  the  grade.  There  are  some  semi-anthracites, 
however,  such  as  the  product  of  the  Cerillos  Mines  of  New 
Mexico,  which  it  is  claimed  have  been  used  with  consider- 
able success  in  suction  gas-producers  and  which  upon  test 
have  been  found  to  yield  i  horse-power  hour  on  1.5 
pounds  of  coal.  This  coal  may  be  purchased  at  not  to 
exceed  $7.50  per  ton  at  the  nearest  railroad  point  in  most 
parts  of  New  Mexico,  Arizona,  West  Texas,  and  southern 
Colorado.  In  Mexico,  mesquite  charcoal  has  been  used 


144  PRACTICAL   IRRIGATION   AND   PUMPING 

successfully,  this  costing  about  $10  per  ton  (gold).  Lignites, 
of  which  great  deposits  are  found  in  the  Dakotas,  have 
been  tried  in  producers  by  representatives  of  the  United 
States  Geological  Survey  with  apparently  favorable  results, 
though  it  is  not  believed  that  this  fuel  has  been  tried  com- 
mercially to  such  an  extent  that  much  can  be  said  about  it 
so  far.  The  other  materials  mentioned  in  the  above  list  are 
of  relatively  low  heating  value  per  pound,  and  unless  they 
can  be  used  in  the  immediate  vicinity  where  found  or  pro- 
duced, it  is  not  likely  that  they  are  of  commercial  value 
as  fuels. 

Electricity. — As  stated  previously  in  discussing  the 
various  types  of  plants,  electric  power  is  by  far  the  most 
convenient  when  it  can  be  obtained,  and  plants  run  by 
electric  current  have  a  further  advantage  in  that  cost  of 
attendance  is  reduced  to  practically  nothing.  It  may  be 
more  expensive  than  power  generated  on  the  premises, 
although  it  is  not  improbable,  in  some  cases  where  plant 
owners  found  electricity  bought  from  a  central  plant  more 
expensive  than  the  power  they  could  generate  themselves 
by  a  gasoline  engine  or  some  other  type  of  prime  mover,  that 
the  owner  of  the  plant  ran  the  same  himself,  and  therefore 
made  no  charge  for  attendance,  and  further  that  he  made 
no  allowance  for  interest,  depreciation,  or  maintenance, 
basing  his  inference  entirely  upon  fuel  cost. 

It  is  customary  for  companies  supplying  electrical  power 
to  base  their  tariffs  upon  a  certain  monthly  charge  based 
upon  the  size  of  the  motor,  which  must  be  paid  regardless  of 
whether  the  machine  is  or  is  not  used.  This  charge  may 
vary,  say,  from  $i  to  $2  per  horse-power  per  month,  and  is 
justified  upon  the  grounds  that  the  company  must  main- 
tain a  certain  equipment  ready  to  supply  this  power  when- 
ever needed,  and  since  this  equipment  is  subject  to  interest 
and  depreciation  charges  it  is  reasonable  that  the  customer 


COST   OF  PUMPING  145 

should  share  this  expense.  In  addition  to  this  fixed  charge, 
there  is  a  power  charge  which  varies  according  to  a  sliding 
scale,  the  greater  the  number  of  kilowatt  hours  used,  the 
less  being  the  charge  per  kilowatt  hour.  This  may  vary 
from  as  much  as  7  cents  per  kilowatt  hour  to  as  low  as 
2  cents.  Another  method  is  to  have  a  minimum  and  a 
maximum  charge  per  kilowatt  hour.  Thus,  say,  for  below 
500  kilowatt  hours  per  month  it  might  be  5  cents  per 
kilowatt  hour,  but  above  500  kilowatt  hours  per  month 
it  might  be  3  cents  per  kilowatt  hour.  In  addition  to 
this  would  also  be  added  the  monthly  fixed  charge  based 
upon  the  size  of  the  motor. 

In  some  cases  with  a  pumping  load  and  for  plants  of 
above  25  horse-power  capacity,  the  charge  is  based  upon 
a  certain  amount  per  horse-power,  as  determined  from  a 
peak  load  indicated  by  a  graphic  or  curve-drawing  watt- 
meter. The  writer  knows  of  contracts  where  the  power 
charge  for  the  season  is  $20  per  horse-power  upon  a  seasonal 
half -hour  peak,  the  season  being  five  months,  and  of  others 
with  a  charge  of  $4  to  $5  per  horse-power  per  month  upon 
a  monthly  peak  of  one  hour.  Such  contracts  are  drawn  up 
with  the  object  of  protecting  the  power  company  against 
excessive  peak  loads  in  large  pumping  plants  with  many 
units,  and  are  supposed  to  encourage  the  plant  operator 
to  exercise  judgment  and  discretion  in  the  use  of  power. 
Peak-load  contracts  are,  however,  not  at  all  justifiable 
in  plants  of  only  one  or  two  units  and  they  lead  to  much 
trouble  and  misunderstanding  unless  the  power  company 
furnishing  alternating  current  is  prepared  to  maintain  a 
very  uniform  frequency  and  voltage.  Power  consumers 
entering  into  such  contracts  should  install  in  their  plants 
their  own  graphic  frequency  meters,  by  which  they  can 
ascertain  if  high  seasonal  or  monthly  peak  loads  are  co- 
incident with  periods  of  high  frequency.  If  such  be  the 


146  PRACTICAL   IRRIGATION   AND   PUMPING 

case,  there  is  considerable  reason  to  believe  that  the  peak 
load  is  due  as  much  to  poor  operating  conditions  in  the 
generating  plants  of  the  power  company  as  to  excessive 
load  conditions  in  the  pumping  plant,  due  consideration 
being  given,  of  course,  to  changes  of  head  and  to  regime 
of  pumping  machinery. 

Still  another  method  of  charging  for  electrical  service 
is  known  as  the  "flat  rate."  This  varies  from  $20  to  $40 
per  rated  horse-power  of  motor  for  a  season  of  five  months. 
The  amount  charged  varies  according  to  locality  and  is 
usually  based  on  a  sliding  scale,  the  larger  the  motor  the 
less  the  rate.  Where  pumps  are  operated  continuously 
and  the  motors  are  loaded  up  to  their  rating,  this  often 
proves  the  most  satisfactory,  both  for  consumer  and  power 
company.  The  figures  given  will  vary  widely  with  different 
companies,  depending  upon  the  size  of  the  central  station, 
upon  whether  it  is  hydraulic  or  steam,  and,  if  the  latter,  the 
cost  of  coal. 

(2)   Interest  on  First  Cost  of  Plant  and  Depreciation 

It  is  very  rarely,  indeed,  that  the  practical  operator  of 
a  pumping  plant  considers  interest  and  depreciation  in  with 
the  cost  of  fuel  as  contributing  to  the  total  cost  of  pumping, 
the  reason  for  this  being,  probably,  that  they  do  not  appear 
as  evident  an  outlay  as  the  fuel  bill.  A  moment's  reflection, 
however,  should  make  it  apparent  that  the  farmer  who 
owns  a  pumping  plant  has  invested  in  it  a  certain  capital 
which  he  may  have  borrowed  and  upon  which  he  may  be 
paying  current  rates  of  interest,  or  it  may  be  that  he  has 
tied  up  in  the  pumping  plant  certain  savings  which  other- 
wise might  be  loaned  at  local  rates.  However  this  may  be, 
it  is  certainly  a  good  principle  to  figure  interest  at  current 
rates  upon  the  cost  of  the  plant  and  add  to  this  the  cost  of 
fuel,  etc.,  since  the  pumping  plant  must  earn  this  interest 


COST   OF  PUMPING  147 

and  enough  to  pay  for  fuel,  otherwise  it  is  certainly  a  poor 
investment.  In  other  words,  good  accounting  would  sug- 
gest that  the  pumping  plant  be  credited  with  the  amount 
of  water  it  produces  at  the  value  of  this  water  either  upon 
the  farm  to  which  it  belongs,  or  upon  its  value  if  sold  to 
surrounding  farms  at  current  water  rates  (the  matter  of 
water  rates  being  entirely  a  matter  of  location,  character  of 
crops  grown,  etc.),  and  the  plant  should  certainly  be  debited 
with  the  cost  of  production  of  this  water.  The  cost  of  pro- 
duction will  include  fuel  and  supplies,  repairs,  attendance, 
interest,  and,  possibly,  depreciation.  If,  at  the  end  of  a 
year,  a  balancing  of  the  ledger  shows  that  the  plant  has  not 
produced  enough  water  of  sufficient  value  to  cover  these 
items,  then  it  is  a  business  failure.  It  may,  of  course,  be 
changed  in  certain  respects,  where  experience  has  shown 
that  defects  interfering  with  its  reliable  or  efficient  oper- 
ation exist,  but  if  the  plant  is  as  reliable  as  others  of  its 
kind,  then  the  best  thing  to  do  is  to  sell  the  plant  for  what 
it  will  bring. 

Depreciation  has  been  mentioned  in  the  above  as  a  pos- 
sibility, since  it  depends  upon  whether  the  pumping-plant 
owner  regards  the  plant  as  "a  going  concern"  or  an  experi- 
ment. If  he  regards  it  as  the  latter,  then  it  is  not  a  per- 
manent improvement  or  asset,  and  no  thought  need  be  given 
to  its  renewal  after  it  is  worn  out.  If,  on  the  other  hand, 
it  is  to  be  regarded  as  a  necessary  appurtenance  to  the 
land  and  as  something  which  gives  to  the  farm  its  value, 
then  it  is  wise  to  make  immediate  provision  against  the 
time  when  it  will  be  consigned  to  the  junk  heap  and  a  new 
equipment  installed.  This  means,  then,  that  in  addition  to 
paying  for  fuel,  supplies,  repairs,  attendance,  and  interest  on 
first  cost,  it  should  earn  yearly  such  a  sum  as  will,  when  put 
at  interest,  have  accumulated  at  the  end  of  such  time  as  it 
may  be  expected  the  plant  will  last,  a  sum  that  will  be; 


148  PRACTICAL  IRRIGATION  AND  PUMPING 

sufficient  to  pay  for  a  new  plant.  It  will  be  seen  that  it  is 
a  difficult  matter  to  estimate  the  yearly  sum  which  should 
be  set  aside,  since,  in  the  first  place,  it  is  a  problem  in 
annuities  and  compound  interest,  and,  in  the  second  place, 
it  is  very  difficult  to  tell  just  how  long  the  plant  will  last. 
In  other  words,  what  number  of  years  is  it  reasonable  to 
assume  must  elapse  before  the  plant  is  so  badly  worn  out 
that  it  will  be  cheaper  to  replace  it  entirely  than  to  attempt 
to  repair  it?  The  problem  is  rendered  all  the  more  difficult, 
since  not  all  parts  of  the  plant  will  depreciate  uniformly. 
Thus  the  probable  life  of  a  boiler  is  about  fifteen  years;  of  a 
steam  engine,  ten  years;  of  a  gas,  gasoline,  or  distillate  en- 
gine, eight  years;  of  a  cheap  centrifugal  pump,  five  years 
(unless  the  water  is  unusually  free  from  sand,  when  it  might 
easily  be  double  that) ;  rubber  belting,  three  years,  leather 
belting,  five  years;  reciprocating  leather-packed,  rubber 
valve  pumps,  five  years;  deep- well  ball- valve  pumps,  five 
years;  wooden  curbing  and  well  timbers,  five  to  seven  years. 
Exceptionally  good  operating  conditions  and  intelligent 
care  may  increase  the  above  periods  by  double  in  the  case 
of  high-grade  pumps,  and  for  plants  in  use  but  a  month  or 
two  out  of  the  year  the  depreciation  may  be  very  slight,  if 
the  machinery  is  properly  housed,  covered,  and  greased 
while  idle.  The  above  periods  may  be  taken  as  a  basis, 
however,  and  either  the  depreciation  figured  on  each  item 
separately  or  the  depreciation  charge  based  upon  the  plant 
as  a  whole.  In  general,  ten  to  twelve  years  will  be  the  life 
of  the  plant  as  a  whole,  except  in  the  case  of  electrically 
driven  very  high-grade  plants,  which  with  proper  care 
should  have  a  life  of  25  years  at  least. 

The  following  table  abstracted  from  Kent's  Handbook 
shows  the  sum  which  must  be  put  away  at  the  end  of  each 
year  at  various  rates  of  interest  to  accumulate  $1,000  at 
the  end  of  different  intervals  of  time. 


COST   OF  PUMPING 
DEPRECIATION  TABLE 


149 


Years  to  Run 

Rate  of  Interest,  Compounded  Annually 

3  per  cent. 

4  per  cent. 

6  per  cent. 

t;    . 

$188.35 

130.51 
112.46 

87.24 
53-77 

$184-63 
I26.6I 
108.53 
83.29 
49-94 

$177-39 
119.13 
101.03 

75-87 
42.96 

7    . 

8 

10     
IS    . 

As  an  illustration,  suppose  that  in  a  district  where  money 
may  be  compounded  at  4  per  cent,  annually,  a  pumping 
plant  costs  $2,500.  Then  for  an  estimated  depreciation 
period  of  ten  years  there  should  be  added  to  the  yearly  cost 
of  operation  account  2.5  X  $83.29  =  $208.22.  If  at  the 
end  of  each  year  this  sum  is  placed  in  a  bank  on  time  de- 
posit at  4  per  cent.,  it  will  at  the  end  of  ten  years  amount 
to  the  original  cost  of  the  plant.  This  scheme,  known  as 
an  amortization  or  depreciation  account  is  regularly  adopted 
and  followed  by  business  firms  employing  machinery  sub- 
ject to  wear  and  tear,  and  it  is  certainly  worthy  of  being 
imitated  by  the  man  who  regards  a  pumping  plant  as  a 
business  proposition  and  not  as  an  experiment  or  play- 
thing. 

In  the  above  illustration  it  will  be  noted  that  the  depre- 
ciation is  about  8>£  per  cent.,  and  if  the  prevailing  rate  of 
interest  in  a  locality  on  real  estate  is,  say,  8  per  cent.,  then 
1 6^"  per  cent,  of  the  original  cost  of  the  plant  must  be 
earned  by  it  annually  in  addition  to  fuel  and  other  items 
of  expense  in  order  that  it  may  be  considered  a  financial 
success. 

(3)   Maintenance  and  Repairs 

In  every  plant,  of  whatever  description,  there  are  things 
constantly  needing  to  be  replaced  or  purchased  new,  and 


150  PRACTICAL   IRRIGATION  AND   PUMPING 

even  in  the  best  plants  small  repairs  will  need  be  made 
from  time  to  time.  Thus  in  gasoline-engine  plants,  batteries 
will  need  replacing,  spark  plugs  will  become  short-circuited, 
valves  may  warp  beyond  possibility  of  grinding,  and  need 
replacing,  etc.,  while  in  a  steam  plant  valves  must  be  re- 
seated, gaskets  replaced,  leaky  boiler  tubes  repaired,  etc. 
Then  occasionally  some  carelessness  in  operation  may  result 
in  a  ruined  bearing,  a  cracked  cylinder  jacket,  and  so 
on.  All  such  repairs  and  replacements  must  be  charged 
against  the  plant  and  enter  into  the  cost  of  operation,  for 
they  will  occur  from  year  to  year  and  no  plant  is  free  from 
them.  The  same  is  true  of  such  items  as  waste,  lubri- 
cating oil,  etc.  None  of  these  items  of  expense  can  be 
neglected  by  the  man  who  really  desires  to  know  how  much 
it  costs  to  pump  water. 

(4)   Attendance 

An  oil-engine  plant  (distillate  or  gasoline),  when  in  good 
condition,  requires  a  relatively  small  amount  of  attention, 
although  it  is  scarcely  true,  as  some  engine  manufacturers 
claim,  that  such  a  plant  can  be  started  in  the  morning  and 
require  no  further  attention  till  it  is  shut  off  at  night. 
While  this  may  be  true  in  theory,  the  practical  operator 
finds  that  a  gasoline  or  distillate  plant  requires  from  one- 
third  to  one-fourth  of  a  man's  time,  when  including  in  the 
course  of  a  season  all  those  vexatious  little  delays  due  to 
faulty  ignition,  choked  or  wet  carburetor,  hot  boxes,  etc. 

For  a  steam  plant  or  producer-gas  plant,  the  constant 
attendance  of  a  more  or  less  skilled  man  is  required  during 
the  entire  season  of  pumping,  and  in  a  large  plant  the  man 
will  need  the  occasional  services  of  one  or  more  helpers. 

Pumps  driven  by  synchronous  or  induction  motors  of 
under  25  to  40  horse-power  will  need  very  little  attention 
except  an  occasional  oiling  and  possibly  replacement  of 


COST   OF   PUMPING  151 

packing.  Larger  plants  up  to  500  horse-power,  these  being 
in  general  those  which  pump  from  surface  sources,  will 
require  a  regular  attendant  who  may,  however,  also  act  in 
many  cases  as  ditch  rider  and  water  master.  Plants  above 
500  horse-power  will  require  the  constant  services  of  a 
skillful  operator  and  a  night  helper  in  case  of  24  hours' 
operation.  The  matter  of  skilled  attendance  is  a  most 
difficult  one  for  large  electrical  pumping  plants,  since  the 
season  is  usually  only  five  months,  and  it  is  impossible  to 
secure  the  services  of  really  capable  operators  for  merely 
that  length  of  time.  Much  of  the  success  of  these  projects 
will  depend  upon  the  management  being  able  to  provide 
12  months'  employment  at  an  attractive  salary  for  men 
able  to  operate  the  pumping  machinery  on  an  efficient  basis 
and  maintain  it  in  the  best  condition  for  reliable  operation. 

It  is  evident,  therefore,  that  to  the  cost  of  power,  interest 
and  depreciation,  maintenance  and  repairs,  there  is  still 
another  item  of  importance  to  be  added  in  order  to  arrive 
at  the  true  cost  of  pumping.  If  a  man  is  employed  as  attend- 
ant who  devotes  a  portion  of  his  time  to  the  care  of  the 
plant,  the  total  number  of  hours  during  the  pumping  season 
when  he  is  so  occupied  should  be  kept  recorded  and  the 
proportional  part  of  his  season's  pay  charged  against  the 
plant. 

In  case  the  owner  of  the  plant  attends  to  it  himself,  his 
natural  tendency  is  to  regard  the  charge  for  attendance 
as  nil.  This  is  fallacious,  however,  for  the  time  so  occupied 
might  be  given  to  other  equally  or  perhaps  more  profitable 
work.  If  possible,  therefore,  the  owner  should  estimate  the 
number  of  hours  devoted  to  the  plant  during  the  season 
and  charge  it  up  at  the  same  hourly  rate  as  would  be  paid 
competent  help  hired  for  the  purpose. 


CHAPTER  XI 

THE    QUESTION    OF    COST    AND    PROFIT    ON    A    SMALL    FARM 
IRRIGATED  BY  PUMPED   WATER 

Elements  of  the  Problem. — The  most  vital  question 
confronting  every  individual,  whether  he  be  an  irrigation 
farmer  considering  the  advisability  of  building  a  pumping 
plant  or  a  business  man  venturing  upon  an  enterprise  of 
any  sort,  is  whether  the  project  will  pay.  This  question  is 
paramount  to  any  question  of  design,  installation,  or  oper- 
ation, but  unfortunately  it  involves  in  its  consideration  and 
solution  more  or  less  definite  knowledge  on  each  of  these 
three  points  since,  until  some  definite  figures  are  available 
on  the  actual  cost  of  obtaining  water,  one  very  essential 
element  in  the  problem  is  lacking.  For  this  reason,  there- 
fore, a  consideration  of  the  question  of  cost  and  profit  has 
been  deferred  until  amounts  of  water  needed  and  types  of 
plants  to  secure  this  water  could  be  discussed  and  some 
better  idea  secured,  perhaps,  of  those  elements  which  enter 
into  the  cost  of  water.  The  latter,  it  must  be  recognized, 
is,  however,  only  one  of  a  number  of  elements  which  de- 
termine the  feasibility  of  a  project  from  the  financial 
standpoint,  and  preliminary  estimates,  which  are  to  deter- 
mine whether  there  is  a  reasonable  expectation  of  profit, 
should,  also,  involve  the  following: 

FIRST — A  Fair  Estimate  of  Yields, — This  should  not  be 
based  upon  any  exaggerated  idea  of  the  fertility  or  richness 
of  the  soil,  or  upon  results  secured,  possibly,  by  some  farmer 
of  the  district  who,  by  unremitting  toil,  fertilizers,  and 
special  knowledge  and  methods,  has  secured  phenomenal 
returns  from  an  acre  or  two  of  ground.  Neither  should 
one  swing  to  the  other  extreme  and  take  as  representative 


THE    QUESTION    OF    COST    AND   PROFIT  153 

the  results  of  the  less  skillful  farmers  or  those  who  through 
lack  of  water,  unskillful  cultivation,  or  insect  or  rabbit 
depredations  made  little  or  no  crops.  The  endeavor  should 
be  made  to  gauge  as  nearly  as  may  be  the  average  crop- 
producing  ability  of  the  land  when  given  intelligent  care 
and  attention,  and  taking  results  over  a  series  of  years  if 
such  information  be  available.  Care  and  discrimination 
are  often  necessary  when  crop  information  for  the  exact 
locality  is  not  available,  in  projecting  such  data  for  other 
districts  than  the  one  in  question,  for  although  climatic  and 
soil  conditions,  altitude,  etc.,  may  be  thought  exactly  the 
same,  it  is  frequently  found  that  the  productive  capacity  is 
widely  different. 

SECOND — The  Cost  of  Crop  Production. — This  will  in- 
clude all  those  expenses  incident  to  the  growth  and  har- 
vesting of  the  crop,  and  are  fairly  well  defined  and  under- 
stood by  those  having  any  practical  knowledge  of 
irrigation. 

THIRD — Shipping  Costs  and  Market  Rates. — Both  of 
these  items  enter  into  the  question  of  returns,  and  should  not 
be  neglected  by  the  individual  who  is  making  a  careful  study 
of  the  possibility  of  profit.  It  is  a  local  matter  entirely,  and 
is  one  requiring  careful  and  full  investigation.  The  matter 
of  suitable  market  and  one  convenient  of  access  is  very 
largely  a  determining  factor  as  to  whether  it  will  pay  to 
invest  in  an  irrigation  scheme,  for  however  cheaply  the 
water  may  be  secured,  if  it  is  in  a  region  remote  from  rail- 
roads and  suitable  markets  it  is  evidently  of  little  use,  except, 
possibly,  in  the  development  of  a  cattle-raising  industry. 

FOURTH — Money  Rates. — Labor  Conditions. — Cost  of 
Materials. — That  these  are  also  involved  in  any  local  set  of 
conditions,  and  will  enter  directly  or  indirectly  into  the 
whole  problem  of  cost  and  profit,  is  too  evident  to  need 
emphasis  or  discussion. 


154 


PRACTICAL  IRRIGATION  AND  PUMPING 


Demonstration  of  a  Problem  in  Cost  and  Profit. — To 

demonstrate  a  consideration  of  the  problem,  a  tract  of  20 
acres  will  be  assumed  in  a  locality  where  alfalfa,  grains, 
melons,  truck  crops,  and  orchard  fruits  (not  citrus)  may 
be  grown.  It  will  be  assumed,  for  convenience,  that  it  is 
proposed  to  drive  the  pumping  plant  by  electric  current, 
although,  of  course,  the  kind  of  power  used  might  be  gaso- 
line or  steam  engine,  and  the  method  of  attacking  the 
problem  would  be  the  same.  The  type  of  plant  is  that 
shown  in  Fig.  26  (Page  119),  and  its  capacity  will  be  taken 
at  300  g.p.m.  The  cost  of  such  a  plant  for  various  total 
lifts  (static,  suction,  and  friction  head)  is  shown  by  the 
accompanying  diagram.  The  costs  given  are  based  on 


Total  Head  in  Feet  , 

8  S  3  8  S  g 

ESTIMATED  TOTAL  COSTS 
DRIVEN  WELL-DEEP  PIT  TYPE 
ELECTRIC  DRIVEN  PUMPING  PLANTS 
CAPACITY  300  G.P.M. 

HORIZONTAL  CENTRIFUGAL  PUMP 
DIRECT  CONNECTED  TO 
2  OR  3  PHASE  -60  CYCLE-  220  VOLT 
INDUCTION   MOTOR 

x 

fs' 

'  y 

x" 

^ 

S* 

X 

^' 

' 

s' 

'"x 

X 

^ 

< 

J 

x" 

x 

x 

f  ** 

, 

X 

X 

s' 

xx 

x 

X 

x 

"*    ,x 

yf 

COSTS  INCLUDE  — 
Pump  and  Motor 
Pipe  -"Valves  -Fittings 
Transformer—  Starting.  Box 
Switches  -Fuses  -Wiring 
Excavation  and  Lining  of  Pit 
'  Well  Sinking   ' 
Installation 
Housing 

x 

~x 
x' 

X 

^s' 

X 

x 

jX 

*•* 

X 

x^ 
.X 

x 

/' 

X 

/' 

s'' 

X 

NC 

)Th 

± 

' 

- 

Maxin 

3De 

3th  'of  I 

»'f«  • 

• 

1 

1 

-I  3 

600   800   1000   1200   1400   1600 
Cost  in'  Dollars 

DIAGRAM  '21 


1800   2000   2200 


actual  Quotations  of  machinery  jobbers,  and  include  esti- 
mated freight  charges  for  100  miles  and  labor  in  erection. 
The  cost  of  a  3-phase  6o-cycle  2  20- volt  mo  tor  "and 
starting  box  is  also  included. 


THE    QUESTION    OF    COST    AND   PROFIT 


155 


Assuming  that  30  acre-inches  will  be  required  by  the 
tract  per  season  (this  including  all  distribution  losses),  it 
will  be  found  that  the  plant  must  operate  about  900  hours. 
Estimating  the  energy  cost  at  3^  cents  per  kilowatt  hour 
(in  advance  of  more  exact  knowledge  of  cost  of  power  when 
total  power  requirements  for  a  given  project  are  known), 
and  allowing  an  interest  charge  of  8  per  cent,  and  depreci- 
ation, taxes,  etc.,  of  8  per  cent.,  we  find  that  the  total  fixed 
and  operating  charges  of  an  electric-driven  pumping  plant 
are  as  shown  in  Diagram  22. 

With  the  operating  and  fixed  charges  known,  the  prob- 


Total  Head—  Ft.  _,  >_» 

t?  C£  —  *  «D  1—  '  W 

5  O  o  o-o  o 

ESTIMATED  TOTALS  OF 
FIXED  AND  OPERATING  CHARGES 
Pl/MPING  PLANTS  OF  300  G.P.M.  CAPACITY 
WORKING  AT  VARIOUS  TOTAL  HEA.DS 
INDUCTION  MOTOR  DRIVE 
DRIVEN-WELL    DEEP  PIT  TYPE 

/ 

* 

s 

/ 

/ 

/« 

' 

/ 

/ 

/* 

/\ 

/ 

/ 

/ 

ENERGY  COST  AS  FOLLOWS 
6600  Volt  current  to  customers 
transformer®  3.5  cents  per  K.W.  hr. 
plus  50  cents  per  month  of  irrigation 
season  per  motor  H.P. 

OTHER  CHARGES  VIZ: 
Interest,  taxes,  amortization  =.16$ 
Attendance,  repairs,  supplies=$5  x  H.P. 
NOTE  i 
For  plant  cost  see  previous  Diagram 

/ 

s 

/ 

s 

100        200        300       400       500        600       700        800 
Yearly  Total  Cost—  Dollars 

'•  DIAGRAM.  22 


900       1000 


able 


returns  may  be  calculated.  The  table  on  page  156 
the  basis  of  estimate  of  net  returns  on  various  crops. 
A  farm  of  20  acres  was  selected  as  representing  probably 
the  limiting  size  for  a'man  of  average  means  starting  in  a 
new  country.  The  division  of  this  acreage  for  the  first  few 
years  is  a  matter  upon  which  considerable  difference  of 
opinion  may  arise.  Some  would  doubtless  attempt  a  large 


156 


PRACTICAL  IRRIGATION  AND   PUMPING 


a  o;  o  S3  co 
§S  =  fcH 

$<<[>•'-> 

10  10  10  o   o     *   o   o   o 

00     cO  OO     HH     QN      •     Tj-    ri"  \O 
^    CO   iO    (S     »-H       •    (N     co   ^ 
M 

Iiil 

^O   *-O   10   O     O            O     O     O 

ity 

^ 

iff 

OOOOO      -QOO 
iO»OiOOO       -OOO 

*]! 

** 

Net  Return 
per  Acre.1 

lOOiONOiO      -OQ 
<^     iO   t^**   CO    cO    co      •    O     O 

*fc       '                                   •     CO    •-. 

Total  Gross 
Return  per 
Acre. 

8  8  8  8  S-5  8    :    : 

o   10  o   o  oo   co  o 

1 

•a 

i 
i 

5     £5     ?   J3   ^   ^     C 
O    10   O    ^     .  ^    Tt     •      • 

£,3 
2  o 

> 

s         2    S2    H2    c     •'     : 

Q             3     3     3     Q 

10      o  .0  o  rh   :    : 

•<t   VO       Tj-                   .          . 

;         ;              ;    ;    c 

f 

U 

|||| 

1  |i:Tll 

<       £  0     U     0  H     J 

o 

' 


. 

1  ^ 

a  g 


^  .2 

SQ 


CD  C 

.5  S, 

O  x 

— '  ^ 


.S        -M 


C    Jj 
QJ      o 

'S  g 

II 

Si 


- 
Sf    AJ    3 

a  -     "3 


L'-C     C-C 


"I  H 
I  ^ 


-  *  IS 

a  « 


- 


- 

3  C 

.£  cj 


THE    QUESTION.   OF    COST    AND    PROFIT  157 

acreage  of  truck  garden  or  orchard,  but  the  general  experi- 
ence is  that  it  is  well  for  several  years  to  have  at  least 
half  of  the  small  farm  in  alfalfa,  which  quickly  comes  to 
maturity  and  provides  a  profitable  crop  requiring  but  little 
labor,  and  enriching  the  soil  so  that  later  it  will  be  available 
for  orchard  and  truck  crops  if  it  is  desirable  to  increase  the 
acreage  given  over  to  them.  The  latter,  however,  while 
more  profitable  than  alfalfa,  are  at  the  same  time  much  less 
certain,  being  more  subject  to  the  effects  of  frost  and  to  the 
ravages  of  insect  pests  and  rabbits.  They  also  require  a  very 
considerable  amount  of  labor  in  production  and  harvesting, 
and  consequently  are  crops  which  should  be  attempted  only 
on  a  small  scale,  except  after  many  years'  experience,  and 
upon  a  co-operative  growing,  picking,  and  selling  basis  with 
the  other  producers.  Onions,  for  instance,  have  been  found 
very  productive  and  profitable  under  irrigation  in  the 
Southwest,  $500  profit  per  acre  having  been  reported,  but 
it  must  not  be  forgotten  that  one  acre  will  require  almost  the 
entire  time  of  at  least  one  man,  and  often  two,  in  properly 
caring  for  the  crop  in  order  that  so  large  a  profit  may  be 
secured.  Consequently,  the  acreage  which  may  be  cared 
for  by  the  individual  grower  during  the  first  years  of  his 
efforts  must  necessarily  be  limited.  The  same  is  true  of 
melons  and  other  crops  giving  large  returns  per  acre.  We 
will,  therefore,  assume  that  the  2O-acre  tract  is  divided 
thus:  10  acres  in  alfalfa,  5  acres  in  orchard,  2  acres  in  onions, 
2  acres  in  melons,  i  acre  in  roads,  buildings,  etc. 

Using  the  above  table  of  estimated  yields  and  net  re- 
turns, we  see  that  the  total  net  return  may  be  as  follows: 

ABC 

10  acres  alfalfa $85          $335          $585 

5  acres  orchard 170  670          1,170 

2  acres  melons 112  212  312 

2  acres  onions 112  212  312 


Profit $479       $1,429       $2,379 


158  PRACTICAL   IRRIGATION   AND   PUMPING 

These  figures  are  based  upon  the  following  values: 

ABC 

Alfalfa  per  ton $10  $15  $20 

Orchard  net  return  per  acre .      100  200  300 

Melons  and  truck  products 

per  acre 100  150  200 

The  net  profits  in  the  above  table  have  not  taken  into 
account  the  cost  of  water,  but,  as  will  be  noted  above,  the 
interest  on  value  of  land  and  improvements  and  costs  of 
production  have  been  taken  account  of  and  allowed  for. 
If,  therefore,  the  fixed  and  operating  charges  on  the  pump- 
ing plant  are  compared  with  these  values,  the  growers'  net 
profit  may  be  determined.  By  Diagram  22  we  have  an 
answer  finally  to  the  question  which  is  of  first  importance 
when  considering  a  pumping  project,  whether  individual  or 
communistic,  this  question  being,  "From  what  depth  will 
it  pay  to  pump  water  for  irrigation  purposes?"  As  will  be 
seen  by  reference  to  Diagram  22,  when  the  total  head 
exceeds  65  feet,  if  prices  correspond  to  condition  A  there 
will  be  no  profit  whatever,  the  cost  of  running  the  pumping 
plant  swallowing  up  the  profits  on  the  farm.  For  condition 
B,  however,  there  is  some  profit  up  to  probably  150  feet, 
and  for  condition  C  there  is  profit  at  almost  any  head 
within  the  practicable  limits  of  mechanical  operation  of 
pumps.  A  means  of  determining  the  approximate  net 
profit  above  all  interest,  depreciation,  and  production 
charges  is  given  by  the  Diagram  22.  Thus  let  us  assume 
that  the  total  head  is  to  be  50  feet  and  that  the  condition  B 
is  supposed  to  prevail.  By  referring  to  the  figure  it  will  be 
seen  that  the  net  profit  is  about  $1,052.  In  closing  the 
discussion  of  this  matter,  it  may  be  remarked  that  the 
problem  is  not  possible  of  general  solution  and  must  be 
considered  with  special  reference  to  local  conditions  and  to 
reasonable  assumptions  on  the  following  points: 


THE    QUESTION    OF    COST   AND  PROFIT  159 

1.  The  size  of  tract  desirable  for  the  individual  farmer 
of  average  means  to  attempt  to  irrigate  by  pumping. 

2.  The  size  of  pumping  plant  necessary  for  this  acreage. 

3.  Reasonable  assumptions  as  to  yields,  cost  of  produc- 
tion, and  market  prices. 

It  is  to  be  also  noted,  since  the  chances  for  profit 
at  a  given  head  are  further  reduced  by  a  pumping  plant  of 
excessive  size  for  the  given  acreage,  that  in  such  estimates 
careful  attention  be  paid  to  the  selection  of  the  proper 
size  of  plant.  Some  light  on  this  matter  may  be  derived 
from  the  following  list  of  plants  in  operation,  with  which 
the  writer  is  personally  familiar,  and  the  acreage  irrigated 
by  each. 

Capacity. 
Gallons  per  min.      Acreage. 

Plant  i 800  120 

Plant  2 375  40 

Plant  3 265  20 

Plant  4 350  40 

In  some  localities  it  is  customary  to  allow  700  gallons 
per  minute  per  100  acres. 

It  will  be  noted,  from  the  diagram  of  fixed  charges  and 
operating  expense  of  pumping  plant,  that  if  the  crop  is 
wholly  alfalfa  there  is  no  profit,  however  small  the  lift, 
when  hay  sells  for  $10  per  ton,  but  that  at  $15  and  $20 
per  ton  one  could  pump  through  total  lifts  of  45  and  85 
feet,  respectively,  and  still  come  out  even ;  consequently,  at 
less  depths  there  will  be  a  small  profit  after  all  interest 
charges,  etc.,  have  been  met. 


CHAPTER  XII 

RESERVOIRS 

Their  Necessity. — It  seldom  requires  more  than  one 
season's  experience  with  a  pumping  plant  to  convince  the 
operator  or  owner  that  a  reservoir  in  connection  with  an 
individual  plant  is  an  eminently  desirable,  if  not  necessary, 
adjunct.  The  pumping  plant,  which  will  operate  day  in 
and  day  out  through  the  entire  season  without  some  serious 
difficulty  arising,  has  not  yet  been  built,  and  these  difficul- 
ties, frequently  causing  a  shut-down  for  several  days  or  a 
week  at  a  time,  quite  invariably  occur  when  the  crop  is  in 
most  need  of  water.  A  shut-down  at  such  a  time,  particu- 
larly with  garden  crops  or  melons  v  may  mean  the  loss  of  the 
crop  and  it  is  highly  important,  therefore,  that  there  be 
some  reserve  supply  of  water  against  such  emergencies. 
There  are  also  other  arguments  in  favor  of  the  reservoir, 
among  which  is  the  fact  that  by  means  of  a  reservoir  it  is 
possible  to  make  use  of  a  greater  "head"  of  water  when 
irrigating  than  is  yielded  by  the  pumping  plant,  since  the 
discharge  of  the  pump  for  several  hours  may  be  retained  by 
the  reservoir  and  then  rapidly  drawn  off  through  a  good- 
sized  ditch  to  the  point  of  use.  By  so  doing,  it  is  possible 
to  cover  a  larger  amount  of  land  with  the  same  quantity 
of  water  than  would  be  possible  with  a  small  stream,  a  fact 
which  every  practical  irrigator  recognizes.  Moreover,  by 
the  use  of  a  reservoir,  it  is  possible  to  irrigate  profitably  a 
much  larger  area  with  a  small  plant  than  would  otherwise 
be  possible,  since  the  plant  may  pump  water  into  the 
reservoir  in  the  night-time  and  in  intervals  between  irri- 
gations, reducing  in  this  way  the  stand-by  expenses  or 

1 60 


RESERVOIRS  l6l 

length  of  time  during  the  year  that  the  large  plant  would 
be  idle,  and  during  which  time  interest  charges  on  the  plant 
and  depreciation  keep  accumulating  the  same  as  though  it 
were  in  operation.  A  reservoir  suitable  for  the  purpose 
should  not  be  an  expensive  piece  of  work,  particularly  in  a 
region  where  clay  or  adobe  soils  may  be  encountered. 

Water-tightness. — The  chief  consideration,  of  course, 
next  to  safety,  is  water-tightness,  but  by  the  use  of  straw 
or  manure  on  an  adobe  bottom  and  banks,  and  trampling 
or  puddling  thoroughly  while  wet  by  driving  sheep  or 
goats  about  the  basin,  a  very  compact  and  water-tight 
surface  may  be  secured.  Pigs  are  equally  effective,  if  al- 
lowed to  wallow  in  the  reservoir  when  it  is  nearly  dry,  and 
a  vigorous  and  sufficiently  long-continued  tramping  by 
men  provided  with  rubber  boots  will  frequently  work  won- 
ders in  preventing  seepage.  Where  adobe  or  clay  is  not 
found  on  the  site,  it  will  pay  to  bring  it  from  a  distance  and 
spread  a  layer  6  to  8  inches  thick  over  the  bottom  and 
sides,  mix  it  with  water,  and  puddle  as  above  described. 
The  use  of  oil,  California  crude,  spread  over  the  inner  sur- 
face of  the  reservoir  in  the  proportion  of  about  2  gallons  per 
square  yard,  will  make  a  comparatively  water-tight  surface, 
even  in  light  material,  and,  of  course,  if  the  expense  can  be 
borne,  a  concrete  lining  not  less  than  4  inches  thick  is  to  be 
recommended.  This  will  cost  from  8  cents  to  12  cents  per 
square  foot,  depending  upon  locality. 

Construction. — A  reservoir  100  feet  in  diameter  to  con- 
tain 4  feet  of  water  may  be  built  with  plows  and  Fresno 
scrapers  for  from  $150  to  $300  complete  with  suitable  out- 
let. Many  have  actually  been  built  considerably  under 
the  latter  amount.  The  bottom  of  the  reservoir  should,  of 
course,  be  level  with  the  surrounding  ground  in  most  cases, 
to  enable  water  to  be  drawn  down  quite  to  the  bottom, 
consequently  the  material  in  the  embankment  should  be 


1 62  PRACTICAL   IRRIGATION  AND   PUMPING 

borrowed  from  outside.  This  material  should  not,  however, 
be  taken  from  a  point  nearer  than  10  feet  from  the  outer  toe 
of  the  embankment,  and  the  borrow  pit  should  be  made  as 
shallow  as  possible. 

Previous  to  building  the  embankment  it  is  frequently  a 
good  idea  to  plow  the  surface  to  be  covered  by  the  embank- 
ment which  should,  so  far  as  possible,  be  built  in  horizontal 


Reservoir 


FIG.  32. — A  safe  method  of  making  an  embankment  for  a  shallow  reservoir. 

layers  rather  than  by  dumping  over  the  end,  as  in  a  railroad 
embankment.  It  should  be  built  not  less  than  i  foot  higher 
than  the  proposed  depth  of  water  in  the  reservoir,  and  its 
width  at  the  base  should  be  from  3  to  4  times  its  height. 
The  horses  and  scrapers  should  travel  along  the  embank- 
ment as  much  as  possible  while  it  is  being  built,  in  order 
to  compact  or  tramp  down  the  material;  and  a  roller,  if  one 
is  available,  will  be  very  effective  in  breaking  up  clods  and 
making  the  embankment  tight. 

Rodents. — A  great  difficulty  and  annoyance  with  a 
reservoir  are  the  breaks  due  to  the  burrowing  of  gophers 
and  other  rodents.  This  difficulty  was  solved  in  one  con- 
spicuous instance  in  the  writer's  knowledge  by  enclosing 
within  the  embankment  at  about  the  middle  a  wire  netting 
of  galvanized  chicken  wire  fencing  of  fine  mesh  which 
reached  vertically  from  the  top  of  the  embankment  to  the 
bottom.  This  serves  to  prevent  rodents  from  making  holes 
entirely  through  the  embankment,  and  while  adding  con- 
siderably to  the  first  cost,  will  doubtless  save  many  times 
its  cost  in  preventing  disastrous  breaks. 

Capacity. — As  to  the  capacity  which  should  be  pro- 


RESERVOIRS  163 

vided  in  a  reservoir,  little  can  be  said  further  than  that  it 
is  mostly  a  matter  of  judgment.  The  larger  the  reservoir, 
the  smaller,  within  certain  limits,  need  be  the  pumping 
plant,  but  a  large  reservoir  means  heavy  losses  from  evap- 
oration and  seepage.  A  safe  rule  to  follow  is  to  provide 
sufficient  storage  for  one  irrigation  of  the  most  tender  crop. 
Thus,  if  among  other  crops  melons  are  being  grown,  this 
would  undoubtedly  be  the  crop  most  susceptible  to  drouth 
and  should  be  provided  for.  If,  for  example,  5  acres  are  in 
this  crop,  20  acre-inches  should  be  stored  which  is  i  ^3  acre- 
feet.  Allowing  for  seepage  and  evaporation,  it  would 
probably  be  well  to  store  at  least  2  acre-feet  for  the 
irrigation  of  this  crop. 

Depth. — In  general,  it  is  advisable  not  to  build  too 
shallow  a  reservoir,  since  this  means  large  water  surface 
compared  with  the  capacity,  and  evaporation  losses  are 
greatly  increased  as  the  surface  exposed  to  wind  and  sun 
is  increased.  A  depth  of  4  feet  should  probably  be  re- 
garded the  minimum,  but  the  difficulties  in  the  building  of 
a  safe  and  water-tight  embankment  will,  in  general,  prevent 
the  adoption  of  a  depth  greater  than  6  feet.  The  following 
diagram  shows  the  diameter  of  circular  reservoirs  required 
to  hold  different  quantities  of  water  with  a  depth  of  3,  4, 
and  5  feet,  as  well  as  the  number  of  cubic  yards  in  the 
embankment  and  the  number  of  hours  required  to  fill  the 
reservoir  by  a  pump  of  5oo-gallon  capacity. 

The  embankments  upon  which  the  diagram  is  based 
are  represented  in  cross-section  on  the  diagram.  They  are 
a  somewhat  heavier  embankment  section  than  is  customary 
practice.  It  is  usual  to  make  the  bottom  width  about  three 
times  the  height.  This,  however,  gives  side  slopes  which 
are  much  too  steep  for  a  safe  and  lasting  embankment. 


164 


PRACTICAL  IRRIGATION  AND  PUMPING 


Capacity  in  Acre  Feet 

H-t  J-» 

o  b« 


2500 


Hours  to  Fill  Pumping  500  G.P.M. 
DIAGRAM   23 

CUBIC  YARDS  IN  EMBANKMENT,  CAPACITY  AND  TIME  OF  FILLING  OF 
SMALL  CIRCULAR  RESERVOIRS 


CHAPTER  XIII 

PRIME  MOVERS 

Steam  Engines  and  Boilers. — With  no  other  prime 
mover  does  fuel  economy  depend  so  much  on  the  type  and 
size  of  engine  as  in  the  case  of  steam  machinery.  In  internal 
combustion  engines,  the  amount  of  fuel  used  per  developed 
horse-power  hour  in  the  smallest  and  cheapest  engine  is  not 
likely  to  exceed  double  that  found  necessary  for  the  largest. 
In  the  steam  engine,  on  the  other  hand,  the  smaller  and 
less-refined  types  are  apt  to  use  over  three  times  as  much 
steam  as  those  of  greater  power  and  more  refinement  in 
design  and  construction.  Since  saving  in  steam  means 
saving  in  coal,  it  is  obviously  of  advantage  to  use  an  engine 
whose  steam  consumption  is  low.  This,  however,  means. an 
engine  whose  cost  is  much  greater  than  the  other,  so  that 
the  question  is  likely  to  resolve  itself  into  a  balancing  of 
interest  charges  against  fuel  saving.  There  are,  in  general, 
two  classes  of  engines  in  the  sizes  necessary  for  pumping- 
plant  service  which  are  suitable,  namely,  the  throttle- 
governed  type  and  the  automatic  type,  both  being  in  the 
class  of  so-called  high-speed  engines.  The  Corliss  engine, 
though  of  high  economy  in  the  larger  sizes,  is  not  so  ad- 
vantageous in  this  respect  in  the  smaller  powers,  besides 
which  it  is  slow  speed  and  per  horse-power  costs  more  than 
the  high-speed  engine.  In  the  rice  irrigation  districts,  where 
several  hundred  horse-power  may  be  used  in  pumping  in 
one  plant,  the  Corliss  type  of  engine  is  economically  justi- 
fiable, but  in  irrigation  pumping  in  the  arid  West  there  will 
seldom  be  found  a  proper  field  for  the  use  of  this  engine 
except  in  central  stations  and  in  certain  cases  where  large 

165 


1 66  PRACTICAL   IRRIGATION   AND   PUMPING 

amounts  of  water  will  be  pumped  at  some  one  point  from 
an  open  water  source. 

Throttle-Governed  Engines. — This  type  is  the  cheapest 
per  horse-power  and  the  least  economical  in  steam  con- 
sumption and  should  not  be  used  in  irrigation  pumping  in 
sizes  over  15  horse-power.  This  type  is  distinguished  by 
the  fly-ball  governor  which  acts  upon  a  valve  in  the  steam 
line  between  the  engine  throttle  and  the  steam  chest.  The 
governor  is  usually  driven  by  a  belt  from  the  main  shaft. 
Such  an  engine  is  likely  to  use  as  much  as  65  pounds  of 
steam  per  delivered  horse-power  hour,  and  such  engine 
should,  in  general,  therefore,  be  connected  to  a  boiler  rated 
at  least  double  the  engine  horse-power.  It  is  very  common 
to  drive  such  an  engine  by  a  boiler  of  the  locomotive  type, 
either  portable  or  on  skids,  and  not  infrequently  the  engine 
is  mounted  either  upon  the  boiler,  or  beneath  the  same, 
and  bolted  down  to  the  skids.  It  is  advisable,  in  general,  to 
use  the  separately  mounted  engine,  since  the  stresses  on  the 
boiler  shell  are  less  severe.  This  type  of  engine  and  boiler, 
while  comparatively  wasteful  of  steam,  is  both  cheap  and 
reliable,  and  a  very  good  plant  to  use  where  steam  coal 
is  not  over  $3.00  per  ton,  delivered,  and  the  power  desired 
is  not  over  15  horse-power. 

Fly- Wheel  Governor  Engines. — The  other  type  of  high- 
speed engines,  which  are  made  in  sizes  from  20  horse-power 
up  to  many  hundreds  of  horse-power,  is  distinguished  by 
having  the  governor  in  the  fly-wheel,  which  acts  upon  the 
valve  mechanism  in  such  a  way  as  to  vary  the  point  of 
cut-off.  In  this  way,  use  may  be  made  of  the  expansive 
force  of  steam,  and  the  engine  is  inherently  more  eco- 
nomical of  steam  than  the  throttle-governed  type.  In  sizes 
up  to  50  horse-power  this  type  of  engine  will  use  about 
40  pounds  of  steam  per  delivered  horse-power  per  hour, 
and  probably  30  or  less  for  sizes  above  50  horse-power. 


PRIME   MOVERS  167 

The  boiler  capacity  for  the  smaller  sizes  should,  therefore, 
be  from  i^  to  iX  larger  than  the  engine  horse-power, 
while  above  50  horse-power  the  rated  boiler  capacity  might 
be  of  approximately  the  engine  horse-power. 

Boilers. — Up  to  6o-boiler  horse-power,  we  believe  that 
no  mistake  will  be  made  in  using  a  semi-portable  locomotive- 
type  boiler  with  water  front  and  open  bottom.  These 
boilers  require  no  setting,  come  provided  with  their  own 
stack,  are  good  steamers,  and  are  easily  cared  for.  Above 
60  horse-power,  probably  it  is  better,  in  a  plant  that  is 
intended  to  be  more  or  less  permanent,  to  use  a  horizontal 
return  tubular,  or  what  is  sometimes  called  a  fire-tube 
boiler.  Such  boilers  are  easily  handled  in  construction,  and 
are  to  be  regarded  as  somewhat  safer  than  the  locomotive- 
type  boiler.  They  require  a  brick  setting,  however,  and  a 
steel  or  brick  stack.  The  boiler  itself  is  cheaper  than  a 
locomotive-type  boiler  of  the  same  size,  but  the  setting 
required  brings  the  final  cost  as  installed  to  above  the 
locomotive  type.  The  working  pressure  to  be  carried  by 
such  boilers  should  not  be  less  than  100  pounds  per  square 
inch,  and  when  purchased,  the  purchaser  should  see  that  a 
reliable  safety  valve  set  for  this  pressure  is  provided. 
Water- tube  boilers,  of  which  there  are  a  great  variety  on 
the  market,  are  undoubtedly  safer  than  either  of  the  types 
just  mentioned.  They  are  intended  for  service  in  which 
there  may  be  sudden  and  wide  variations  in  the  steam 
demand  (as  in  street  railway  or  general  power-plant  service), 
and  are  therefore  not  necessary  in  a  plant  wherein  the  load 
is  quite  uniform.  They  are  considerably  more  costly  than 
fire-tube  boilers  and  the  setting  is  likewise  more  costly. 
It  is  doubtful  if  their  use  is  justifiable  in  plants  develop- 
ing less  than  200  horse-power,  which  is  about  the  mini- 
mum size  in  which  most  of  them  are  manufactured. 

Auxiliaries  and  Fittings. — In  large  plants  it  will  usually 


1 68  PRACTICAL  IRRIGATION  AND   PUMPING 

pay  to  put  in  a  surface  or  jet  condenser,  using  the  water 
pumped  to  act  as  the  cooling  medium,  but  in  a  small  plant, 
or  say  in  one  of  less  than  100  horse-power,  the  extra  cost 
of  the  condensing  apparatus  will  scarcely  be  warranted  by 
the  saving  in  fuel.  An  efficient  steam  separator  should  be 
used  in  the  steam  line  between  the  boiler  and  engine,  and 
in  any  plant  above  20  horse-power  a  boiler  steam  pump 
should  be  provided  in  addition  to  the  injector  usually  fur- 
nished with  the  locomotive- type  boiler.  In  plants  of  above 
50  horse-power  the  injector  is  rarely  used  at  all,  and  it  is  a 
measure  of  safety  to  provide  boiler  steam  pumps  in  dupli- 
cate. The  boiler  and  engine  should  be  placed  as  closely 
adjacent  to  each  other  as  possible  to  avoid  heat  losses  by 
radiation  in  long  steam  pipes,  and  it  will  be  found  not  very 
expensive  to  lag  the  steam  piping  with  effective  asbestos 
covering,  which  may  be  purchased  in  molded  form  ready 
for  application  both  to  pipe  and  fittings.  Steam  engines  of 
the  types  above  mentioned  should,  if  possible,  be  provided 
with  automatic  oiling  systems,  and  since  engines  are  often 
very  poorly  protected,  by  the  building,  from  dust  and  grit, 
it  is  better  to  choose  an  engine  in  which  the  crank  and  all 
reciprocating  parts  are  completely  enclosed. 

Boiler  Insurance. — An  important  matter,  to  which  little 
or  no  attention  is  generally  paid  by  the  owners  of  small  steam 
plants,  is  that  of  boiler  insurance.  A  boiler  is  a  potential 
agent  of  destruction,  ^and  too  much  attention  cannot  be 
paid  not  only  to  its  proper  operation,  but  to  the  detection 
of  dangerous  flaws  and  defects,  which  may  result  in  serious 
disaster  under  the  best  conditions  of  operation.  The  ser- 
vices of  expert  boiler  inspectors  are  obtained  when  boiler 
insurance  is  carried,  and  it  is  always  worth  the  trifling 
expense  involved.  Those  purchasing  second-hand  boilers, 
should  always  insist  on  being  furnished,  together  with  the 
boiler,  insurance  in  some  well-known  boiler-insurance  com- 


PRIME   MOVERS 


169 


pany,  for  at  least  one  year.     Such  insurance  is  the  best 
possible  recommendation  of  the  condition  of  the  boiler. 


Gasoline  Engines 

This  type  of  prime  mover  is  so    common    that    de- 
scription   is    unnecessary. 


find    manufactured    to- 


pic. 33. — An  excellent  example  of  hit-and-miss  governed   gasoline  engine  suitable 
for  driving  pumping  machinery. 

day    a    great    number  of  reliable,  well-designed  engines, 
such     as     the     Stover,     Fairbanks-Morse,    International 


170  PRACTICAL   IRRIGATION   AND   PUMPING 

Harvester,  Dempster,  and  many  others,  any  one  of 
which,  with  intelligent  care  and  attention,  will  give  satis- 
factory service. 

Difficulties  in  Operation. — Gasoline  engines  in  general 
are,  however,  subject  to  numerous  ailments  which  are  a 
source  of  much  delay  and  vexation.  In  nine  cases  out  of 
ten,  the  trouble  with  a  gasoline  engine  which  refuses  to  run, 
may  be  found  in  the  electric  ignition  or  sparking  apparatus. 
The  first  thing  is  to  see  that  all  binding  post  thumb-screws 
are  tight  on  the  spark  plug,  batteries  and  induction  coil, 
and  that  the  ends  of  the  wires  at  these  points  are  scraped 
bright  and  the  binding  points  are  also  clean  of  oil  and  dirt. 
The  spark  plug  itself  sometimes  becomes  foul  with  soot,  or 
the  points  become  so  worn  that  a  spark  cannot  be  produced, 
in  which  case  it  should  be  cleaned  or  replaced  by  a  new  plug, 
as  the  case  may  be.  If,  after  all  this  has  been  attended  to, 
a  spark  still  cannot  be  produced,  the  trouble  probably  will 
be  found  to  lie  in  worn-out  batteries.  When  a  magneto  is 
used  instead  of  batteries  after  starting,  as  is  a  practice 
always  to  be  recommended,  a  refusal  of  the  engine  to  con- 
tinue running  after  the  batteries  are  switched  off  may 
sometimes  be  traced  to  the  magneto  pulley,  which  will  not 
keep  up  to  speed  because  the  face  of  the  fly-wheel  against 
which  it  runs  is  covered  with  grease,  in  which  case  the  rem- 
edy is  obvious;  or  the  springs  in  the  magneto  pulley  which 
force  it  against  the  fly-wheel  face  may  have  become  so 
weakened  that  they  are  unable  to  force  the  pulley  sufficiently 
hard  against  the  fly-wheel.  If  the  ignition  apparatus  has 
been  placed  in  good  condition,  further  failure  to  start  may 
be  due  to  troubles  in  the  carburetor  or  mixing  device. 
Most  carburetors  are  provided  with  a  small  orifice  through 
which  the  gasoline  sprays  and  is  mixed  with  the  air,  and  if 
this  orifice  becomes  stopped  up  from  any  cause,  not  enough 
gasoline  will  be  drawn  into  the  cylinder  to  keep  the  engine 


PRIME   MOVERS  171 

in  operation  after  the  first  few  explosions,  which  are  usually 
obtained  by  pouring  a  small  quantity  of  gasoline  into  the 
cylinder  through  the  pet-cock  always  provided  on  top  of 
the  cylinder.  Sometimes  it  is  impossible  to  obtain  the 
first  explosion  by  pouring  gasoline  into  the  cylinder,  which 
may  be  due  to  the  fact  that  an  excess  of  gasoline  has  been 
used,  which  should  be  removed  by  turning  over  the  engine 
several  times  with  the  pet-cock  and  exhaust  valve  held 
open,  after  which  a  smaller  quantity  should  be  tried.  Poor 
gasoline  may  also  cause  trouble  at  starting.  Engine  naph- 
tha, which  is  a  distillate  with  a  higher  boiling  point,  and 
which,  therefore,  does  not  vaporize  as  readily  as  gasoline,  is 
frequently  sold  to  the  consumer  in  place  of  gasoline,  and 
great  difficulty  is  sometimes  experienced  in  starting,  if  this 
is  the  case.  The  difficulty  may  be  overcome  by  using 
high-grade  gasoline  for  starting  and  warming  up  the  cyl- 
inder, after  which  the  lower-grade  oil  will  vaporize  prop- 
erly and  the  engine  will  continue  to  run,  or  the  naphtha 
itself  may  be  warmed  slightly  (much  care  being  employed 
not  to  ignite  it  in  so  doing),  after  which  it  may  be  squirted 
into  the  cylinder  and  allowed  to  stand  a  few  moments  be- 
fore the  engine  is  turned  over  and  sparked,  the  interval  of 
time  being  necessary  to  allow  the  naphtha  to  evaporate. 

Another  difficulty  may  lie  in  the  gasoline  pump  and 
valves,  which  may  be  leaky,  or  the  suction  pipe  leading 
from  the  fuel  tank  to  the  pump  may  leak  air,  any  one  of 
which  will  cause  the  failure  of  the  engine  to  secure  sufficient 
gasoline  and  will  result  in  almost  immediate  stopping.  The 
existence  of  this  trouble  may  be  ascertained  by  opening  up 
the  carburetor,  which  can  usually  be  done,  and  operating 
the  pump  by  hand  a  few  times  to  see  if  the  gasoline  is 
pumped  in  good  quantity. 

Another  cause  for  trouble  frequently  lies  in  the  suction 
and  exhaust  valves,  particularly  the  latter,  which  may  not 


172  PRACTICAL   IRRIGATION  AND   PUMPING 

be  tight,  or  which  may  not  open  or  close  properly  or  at  the 
proper  position  in  the  stroke.  The  tightness  of  the  valves 
and  piston  rings  may  be  tested  by  bringing  the  engine  to 
compression  and  holding  it  there.  If,  after  a  moment  or  so, 
the  fly-wheel  can  easily  be  forced  over  the  back  dead  point, 
it  shows  that  the  valves  or  piston  rings  are  leaky.  This 
may  be  due  to  an  accumulation  of  grease  or  tar  on  the  valve 
seats  or  to  wearing  of  the  seats,  which  in  the  latter  case 
necessitates  regrinding  by  use  of  an  ordinary  carpenter's 
brace  and  emery  dust.  Audible  knocking  in  the  cylinder  and 
back-firing  (an  explosion  which  sends  the  engine  backwards) 
are  always  due  to  the  spark  occurring  at  the  wrong  time. 
The  sparker  should  for  best  results  trip  when  the  crank  is 
a  little  below  the  back  dead  centre,  but  care  should  be 
exercised  not  to  have  this  too  much.  When  the  centre  line 
of  the  crank  makes  an  angle  of  about  10  degrees  with  the 
centre  line  of  the  cylinder,  it  is  probably  in  the  best  position. 
A  final  word  is  advisable  on  proper  attention  to  the 
position  of  the  needle  valve  on  the  carburetor,  which  reg- 
ulates the  flow  of  gasoline  to  the  cylinder.  At  starting,  this 
may  be  quite  well  opened,  but  after  the  load  has  been  put 
on,  the  needle  valve  should  be  closed  to  the  point  at  which 
the  engine  will  just  carry  the  load,  or  keep  up  to  speed  and 
explode  regularly,  with  an  occasional  miss.  One  miss  in 
every  ten  or  twelve  explosions  shows  that  the  governor  is 
working  and  the  engine  probably  amply  supplied  with  fuel. 
The  importance  of  this  lies  in  keeping  down  the  fuel  con- 
sumption. The  writer  has  frequently  been  able,  by  proper 
adjustment  of  the  needle  valve,  to  very  materially  reduce 
the  amount  of  fuel  consumed  by  the  engine,  in  the  case  of 
one  plant  which  he  was  asked  to  examine,  the  owner  finding 
that  an  adjustment  of  the  needle  valve  reduced  the  daily 
fuel  consumption  from  8  to  5  gallons  per  day,  a  reduction 
in  expense  of  pumping  which  greatly  increased  his  chances 


PRIME   MOVERS 


173 


for  profit  on  the  season's  crop.  A  cloud  of  smoke  from  the 
exhaust  pipe  of  a  gasoline  engine  indicates  either  one  of 
two  things,  too  much  gasoline  or  too  much  lubricating  oil 
in  the  cylinder  and  the  remedy  is  obvious.  The  circulating 
water  which  cools  the  cylinder  should  be  only  so  much  in 


GEAR 
StllELD 


FIG.  33A. — A  modern  high-grade  gasoline  engine  with  parts  named. 

quantity  as  will  keep  the  cylinder  and  jacket  cool  enough 
to  allow  one  to  keep  his  hand  on  the  jacket  for  a  moment 
or  so;  in  other  words,  the  water  as  it  comes  from  the  jacket 
should  be  at  nearly  boiling  temperature. 

Over-Rating. — A  common  difficulty  with  many  of  the 
cheaper  grades  of  gasoline  engines  is  that  not  only  are 
they  flimsy  and  weak  in  certain  parts,  but  they  are  over- 
rated as  to  horse-power.  An  engine  with  a  very  small 
cylinder  may  be  made  to  develop  a  large  horse-power  by 
increasing  its  speed  to  far  above  what  would  be  considered 
good  practice,  and  this  is  what  is  actually  done  with  some 
of  the  poorer  grades  of  engines.  The  speed  of  an  engine 


174  PRACTICAL   IRRIGATION  AND   PUMPING 

below  6  horse-power  should  not  exceed  300  revolutions  per 
minute,  and  above  that  it  should  decrease  from  250  down 
to  200  or  less  in  the  larger  engines.  The  only  true  way  in 
which  to  determine  the  power  of  engines  is  by  a  brake  test 
and  all  reliable  engine  manufacturers  test  in  this  way  each 
engine  made  before  it  is  shipped  out,  to  be  sure  that  it  will 
develop  its  rated  horse-power  or  more. 

Oil  Fuels. — Gasoline  is  only  one  of  a  great  number  of 
products  of  the  distillation  of  crude  petroleum,  and  it 
differs  from  those  known  as  distillates  by  being  lighter 
and  more  volatile.  The  distillates  are  technically  low- 
graded  kerosenes.  They  have  about  the  same  specific 
gravity,  but  are  not  as  clear  and  limpid  as  kerosene,  nor 
as  uniform  in  specific  gravity. 

The  specific  gravity  of  the  various  oil-fuel  products  is 
by  no  means  fixed,  so  that  gasoline  may  vary  in  density 
through  a  considerable  range  and  still  be  called  gasoline, 
and  the  same  is  true  of  other  products.  There  are  purchas- 
able, indeed,  several  grades  of  gasoline,  the  lightest  being 
very  volatile,  and  the  heaviest  being  so  nearly  like  kero- 
sene that  it  is  difficult  to  start  an  engine  when  using  it,  and 
to  use  it  regularly  as  a  fuel,  a  carburetor  surrounded  by  a 
jacket  is  necessary,  through  which  cooling  water  from  the 
engine  cylinder  jacket  is  allowed  to  circulate,  or  sometimes 
the  exhaust  gases  are  so  used. 

The  character  of  gasoline  varies  somewhat,  also,  with 
the  field  from  which  the  crude  oil  from  which  it  has  been 
distilled,  has  been  drawn.  Thus,  gasoline  from  the  crude 
oils  of  the  Kansas  and  Oklahoma  fields  is  most  easily  used 
in  a  gasoline  engine  when  it  has  a  specific  gravity  of  from 
•753~-745  (s8°~6o°  Baume);  from  Texas  and  California 
crudes  it  should  have  a  specific  gravity  of  about  .76  (56° 
Baume).  Gasoline  and  other  oils  are  classified  in  com- 
merce with  regard  to  weight  usually  by  the  Baume  scale, 


PRIME   MOVERS 


175 


so  that  in  buying  "60  gasoline"  one  buys  not  gasoline  of 
.60  specific  gravity,  but  gasoline  which  has  a  gravity  of 
60°  "Baume/'  i.e.,  a  specific  gravity  of  0.745.  Much 
confusion  and  misunderstanding  is  apt  to  result  through  a 
common  misuse  of  the  term  gravity  when  referring  to  the 
"Baume"  scale. 

The  following  table  gives  an  understanding  of  the  dis- 
tinction between  the  different  grades  of  fuel  oils  and  the 
allowable,  or  distinguishing,  range  in  specific  gravity. 


Oil 


TABLE  X 

Specific  Gravity     Baume 


Flash  Point 


Gasoline 

Engine  naphtha 

Kerosene 

Distillates 

Solar  oil  . 


Crude  oils: 

Pennsylvania .... 
West  Virginia .... 

Ohio 

Oklahoma- Kansas , 

Texas 

California .  . 


76-70 
848 
80 

.91-. 8* 
86 


.806 

•794 
.804 

.851 
.913 
.964 


56-70 


24-30 
34 


43-7 
46.2 
44.0 

34-5 
23.2 

15-2 


250°  F. 
100-250°  F. 


It  will  be  understood  that  the  distillates  vary  in  "grav- 
ity" according  to  the  source  of  the  crude  oil  from  which 
they  are  derived,  and  that  the  flash  point  will  also  vary 
according  to  the  completeness  with  which  the  distillation 
has  been  carried  on.  Distillates  with  high  flash  point  are 
safer  to  store  and  use  than  others,  since  they  are  less  likely 
to  give  off  inflammable  vapors  at  low  temperatures,  which 
become  a  source  of  danger  from  sparks  or  carelessly  disposed- 
of  matches. 

Distillate  Engines. — The  rapidly  increasing  use  of  gas- 
oline in  automobiles,  motor  boats,  and  for  other  purposes,  is 


176  PRACTICAL   IRRIGATION   AND   PUMPING 

already  beginning  to  be  reflected  in  a  rapidly  advancing 
price  for  this  fuel,  so  that  the  attention  of  engine  designers 
and  manufacturers  has  been  directed  for  some  time  to  the 
problem  of  utilizing  the  cheaper  grades  of  fuel  oils  from 
crude  oil  upwards.  When  an  oil  of  less  volatility  than  gas- 
oline is  used  in  an  engine,  special  means  must  be  taken  to 
secure  its  proper  combustion  in  the  engine  cylinder,  and 
the  difficulties  in  accomplishing  this  increase  as  the  oil 
increases  in  density.  To  overcome  these  difficulties, 
special  carburetors  are  sometimes  used  in  which  the  oil  is 
more  or  less  highly  heated  in  order  to  increase  its  volatility 
and  the  consequent  ease  with  which  it  will  combine  with 
air  to  form  an  explosive  mixture,  while  in  other  engines  the 
design  of  the  cylinder  is  so  altered  from  the  usual  designs  as 
to  provide  the  special  conditions  necessary  for  the  combus- 
tion of  heavy  oils. 

In  the  first  case,  carburetors  and  mixing  devices  have 
been  devised  which  will  enable  the  satisfactory  use  of  kero- 
sene and  the  Mgher  grade  of  distillates  in  an  engine.  The 
greatest  difficulty  in  such  cases  is  found  in  getting  the 
engine  started  on  the  low-grade  oil,  and  usually  means  are 
provided  for  starting  on  gasoline  and  running  on  it  for  a 
short  while  or  until  the  carbureting  device  (heated  either 
by  exhaust  gases  or  cooling  water  from  engine  jacket)  has 
become  sufficiently  hot  to  produce  the  required  volatility 
of  the  heavy  oil,  when  the  gasoline  supply  is  cut  off,  and 
the  engine  continues  to  operate  on  the  heavy  oil. 

The  writer  has  seen  Solar  oil  used  with  entire  success 
in  a  Fairbanks-Morse  engine  provided  with  such  a  device, 
the  only  difficulties  being  more  or  less  rapid  accumula- 
tions of  tar  in  the  combustion  chamber  and  on  the  valves 
and  seats,  etc.  There  is  also  a  heavy  residual  oil  formed 
which  either  is  burned  and  comes  out  of  the  exhaust  as  a 
black  smoke  or  escapes  by  the  piston  rings  and  accumu- 


PRIME   MOVERS 


177 


lates  in  the  crank  case.  The  presence  of  this  oil  in  the 
cylinder  obviates  the  necessity  of  lubrication,  and  the 
accumulation  in  the  crank  case  has  a  value  as  a  fuel  or 
lubricant. 

When  the  oil  increases  in  density  or  its  volatility  is 
lessened,  the  means  just  described  are  found  inadequate, 


1 

1 1  -H 

I!! 


.a  6 
•8  „ 


• 

l-i 


11 
f 


and  a  special  engine  must  be  used.     There  has  been  on 
the  market  for  some  years  an  engine  known  as  the  Hornsby- 


178  PRACTICAL   IRRIGATION   AND   PUMPING 

Akroyd  engine  (it  is  now  manufactured  in  this  country) 
which  is  well  adapted  to  the  use  of  kerosene  or  the  better 
grades  of  distillates,  such  as  Solar  oil  or  any  oil  having  a 
gravity  of  24°  Baume  or  lighter.  It  will  not,  however, 
operate  on  crude  oils.  This  engine  is  provided  with  a 
vaporizing  chamber  which  is  first  heated  to  a  red  heat  by 
external  means  and  into  which  the  fuel  oil  is  injected  and 
vaporized.  On  the  compression  stroke  of  the  engine,  air 
being  forced  into  the  vaporizing  chamber,  combustion  re- 
sults, and  is  succeeded  by  a  power  stroke,  exhaust  stroke, 
and  air  suction  stroke  similar  to  any  four-stroke  cycle 
engine.  After  starting,  the  heat  of  combustion  keeps  the 
vaporizing  chamber  at  the  necessary  temperature  for  vapor- 
ization and  consequently  no  electric-ignition  system  is  used. 
A  similar  principle  is  used  in  the  Mietz  and  Weis  engine. 

No  particular  difficulty  is  experienced  in  the  practical 
operation  of  these  engines  except  in  cold  weather,  when  it 
is  sometimes  necessary  to  warm  a  heavy  oil  in  order  that 
it  may  become  sufficiently  fluid  to  flow  through  the  pump 
which  injects  the  oil  into  the  vaporizing  chamber.  These 
engines  are  made-  in  sizes  of  from  10  to  100  horse-power 
and  offer,  therefore,  to  the  owner  of  the  small  pumping 
plant,  an  extremely  economical  and  very  satisfactory 
prime  mover.  They  cost  about  50  per  cent,  more  than 
a  good  gasoline  engine  of  the  same  power. 

The  Hornsby- Akroyd  type  engine,  when  used  with  heavy 
oils,  soon  accumulates  a  considerable  quantity  of  tarry 
residues  in  the  vaporizing  chamber  which  interferes  with 
vaporization.  This  difficulty  is  surmounted  by  having 
several  chambers  at  hand  and  replacing  the  one  in  use  by 
a  clean  one  after  24  or  36  hours  of  operation.  This  is  a 
simple  operation  requiring  merely  the  unscrewing  and 
screwing  up  again  of  the  nuts  on  the  studs  by  which  the 
chamber  is  attached  to  the  main  body  of  the  cylinder. 


PRIME    MOVERS 


179 


The  old  head  may  then  be  cleaned  and  made  ready  again 
to  be  placed  on  the  engine. 

An  engine  which  has  come  into  great  prominence  in 
the  past  few  years  because  of  its  remarkable  fuel  economy, 


FIG.  35. — An  internal  combustion  engine  of  about  15  horse-power,  designed  to  utilize 
kerosene,  distillates,  Solar  oil,  etc.    Made  in  a  large  range  of  sizes. 

is  known  as  the  Diesel  engine.  This  is  a  four-stroke  cycle 
engine  of  very  heavy  proportions,  due  to  the  extreme  pres- 
sures realized  in  the  cylinder  (600  pounds  per  square  inch 
or  more),  and  only  built  (in  this  country  at  least)  in  sizes 
of  over  125  horse-power.  It  is  primarily  a  crude-oil  engine, 
and  will  work  satisfactorily  on  any  oil  not  heavier  than 
19°  Baume,  and  which  does  not  contain  more  than  i>^ 
per  cent,  of  water.  No  electric-ignition  system  is  used, 
but  a  component  part  of  the  engine  is  an  air  compressor 
for  starting  and  for  injection  of  the  fuel.  A  slightly  modi- 
fied and  less  heavy  engine  of  this  type  put  out  by  an 


l8o  PRACTICAL   IRRIGATION   AND   PUMPING 

American  manufacturer  is  in  successful  use  in  California 
on  the  crude  oil  of  that  State,  with  its  troublesome  asphal- 
tum  base.  The  Diesel  engine  uses  less  than  i  pound  of 
oil  per  horse-power  per  hour  and  is  destined  to  have  an 
important  future  in  the  Southwest  and  in  California,  where 
oil  fuel  is  abundant  and  cheap.  Its  use  in  relatively  small 
pumping  plants  is,  however,  exceedingly  questionable  in 
view  of  the  more  or  less  expert  attendance  required  and  in 
view  of  the  fact  that  it  costs  about  double  the  price  of  a 
gasoline  engine  or  steam  plant  of  equivalent  power. 

The  Gas  Producer  and  Engine. — Principles  of  Opera- 
tion.— The  elementary  action  of  the  gas  producer  is  familiar 
to  all  in  the  example  of  the  ordinary  heating  stove,  which, 
after  being  well  filled  with  fresh  coal,  will  sometimes  experi- 
ence a  mild  explosion  due  to  the  formation  and  ignition 
of  gas.  The  gas  is  formed  by  slow  combustion  without 
sufficient  draft  or  air  supply  to  produce  complete  oxidation 
or  burning  of  the  carbon  of  the  coal.  The  same  principle 
is  made  use  of  in  the  gas  producer  in  which  we  have  a 
large  retort  lined  with  fire-brick  in  which  coal  is  burned  in 
the  presence  of  an  inadequate  air  supply,  causing  the 
formation  of  an  explosive  gas  which,  however,  is  caused  to 
explode  in  an  engine  cylinder  and  do  useful  work  in  driving 
forward  the  piston  of  the  engine.  Since  the  gas  formed  in 
the  process  is  used  directly  and  its  heating  power  given  out 
directly  in  the  engine  cylinder,  it  is  evidently  a  much 
more  economical  method  of  using  the  coal  than  burning 
the  gases  given  off  by  this  coal  under  a  boiler,  generating 
steam  thereby,  which  is  transmitted  a  greater  or  less  dis- 
tance through  pipes  and  finally  used  in  a  steam  engine. 
Aside  from  any  questions  of  practical  operation,  therefore, 
it  would  be  apparent  to  any  one  that  a  gas-producer  plant 
would  be  much  more  economical  in  fuel  than  a  steam 
plant.  While  the  process  of  generating  the  gas  as  above 


PRIME  MOVERS  l8l 

outlined  seems  simple,  the  difficulties  in  cooling,  cleaning, 
and  regulating  the  gas  flow,  and  of  firing,  cleaning,  and 
poking  the  producer,  to  say  nothing  of  finally  utilizing  the 
gas  in  the  engine  cylinder,  all  have  to  be  overcome  and 
solved  before  the  plant  can  be  called  a  commercial  success. 
Up  until  the  last  half-dozen  years,  the  producer  plant  was 
a  thing  to  be  avoided  by  the  man  not  wilfully  seeking 
trouble,  but  the  genius  of  American  designers  and  engineers, 
backed  up  by  several  years  of  practical  experience,  has 
finally  evolved  plants  made  by  several  manufacturers,  which 
under  the  right  kind  of  management  and  when  provided 
with  the  right  kind  of  coal,  give  no  more  difficulty  in 
operation  than  many  steam  plants. 

The  type  of  producer  best  adapted  for  plants  of  the 
size  usually  adapted  for  small  pumping  plants  is  the  suc- 
tion producer.  In  this,  the  air  passing  through  the  producer 
is  caused  to  flow  by  the  suction  effect  of  the  engine,  which 
upon  the  suction  stroke  takes  in  a  charge  of  gas.  There  is, 
therefore,  no  gas  storage  and  the  amount  of  air  passed 
through  the  producer  varies  directly  with  the  speed  of  the 
engine.  The  plant  consists  of  (i)  the  producer  proper, 
with  its  accessories,  such  as  a  blower  and  feed-hopper; 
(2)  a  vaporizer  (usually)  in  which  the  hot  gas  coming  from 
the  producer  is  cooled  by  coming  in  contact  with  water- 
cooled  surfaces;  the  air  taken  into  the  producer  by  suction 
being  made  to  pass  through  the  vaporizer,  takes  up  moisture 
besides  being  heated,  and  thus  increases  the  efficiency  of 
gas  production.  After  leaving  the  vaporizer,  the  gas  passes 
into  (3)  the  scrubber,  where  tarry  substances  and  dust 
are  removed  by  the  gas  coming  in  contact  with  a  spray  of 
water,  and  being  made  to  pass  through  thick  layers  of 
moist  coke.  Leaving  the  scrubber,  the  gas  next  passes 
through  (4)  a  purifier  in  which  is  excelsior,  sawdust,  and 
the  like,  intended  to  remove  the  moisture  and  any  re- 


1 82  PRACTICAL  IRRIGATION  AND  PUMPING 

maining  suspended  impurities.  Anthracite  coal  and  coke 
or  charcoal  are  the  fuels  best  adapted  to  be  used  in  this 
type  of  producer,  but  bituminous  producers  are  being 
experimented  with  by  many  of  our  foremost  engineering 
establishments  and  it  will  doubtless  be  only  a  matter  of 
time  till  the  chief  trouble  now  experienced  in  the  use  of 
bituminous  coal  will  be  removed,  namely,  the  dust  and 
tarry  products  formed  which,  unless  effectually  removed, 
prevent  the  satisfactory  operation  of  the  engine.  The 
bituminous  producers  so  far  devised  have  proven  quite 
reliable,  but  their  cost  is  very  much  greater  than  the 
ordinary  suction  anthracite  producer  plant.  The  latter 
are  made  in  sizes  of  not  less  than  25  horse-power,  a  com- 
plete plant  and  an  engine  of  this  size  costing,  approxi- 
mately, $1,800  at  the  factory. 

Conditions  Warranting  Adoption  of  Gas-Producer  Plant. — 
The  writer  does  not  recommend  this  type  of  power  plant 
except  under  these  conditions: 

1.  When  anthracite,  coke,  or  charcoal  are   available, 
or   a   semi-anthracite,    the   equivalent   of   New   Mexican 
Cerillos. 

2.  When  the  power  required  is  in  excess  of  50  horse- 
power. 

3.  Where  steam  coal  costs  over  $3.50  per  ton,  gasoline 
over  1 8  cents  per  gallon,  distillate  oils  over  9  cents  per  gal- 
lon, and  electricity  is  either  not  available  or  will  cost  on 
the  average  over  5  cents  for  horse-power  hour. 

4.  When  attendance  of  intelligence  and  skill  is  avail- 
able to  run  it. 

We  caution  the  prospective  plant  owner  against  adopt- 
ing a  producer-gas  power  plant  except  after  a  most  careful 
inquiry  into  its  merits  and  defects  as  compared  with 
other  kinds  of  power,  and  he  should  be  particularly  careful 
not  to  base  his  judgment  upon  fuel  economy  alone,  for 


PRIME  MOVERS  183 

reliability  or  ability  to  pump  water  when  crops  most  need 
it  is  worth  more  than  all  the  coal  which  might  be  saved  in 
a  year's  operation  by  the  producer  plant  as  compared 
with  steam.  The  average  pumping-plant  operator  can  ill 
afford  to  lose  a  crop  because  he  has  a  plant  which  fails 
him,  largely  for  want  of  knowledge  of  how  to  run  it,  at  the 
most  critical  time,  probably,  in  the  whole  season.  Men 
given  to  enthusiasm  over  new  mechanical  devices  and 
methods  are  apt  to  regard  the  producer-gas  plant  as  the 
key  to  the  whole  problem  of  cheap  pumping  and  either 
purchase  such  a  plant  themselves  or  induce  their  neigh- 
bors to  do  so,  although  they  have  but  the  most  meagre  and 
superficial  idea  of  the  kind  of  fuel  needed,  the  practical 
operating  difficulties,  and  of  the  economic  conditions  which 
make  such  a  plant  needed  or  advisable. 

Electric  Motor  Drive. — Practically  all  irrigation  pump- 
ing plants  with  electric  drive  use,  or  will  use,  three-phase 
alternating  current  of  frequency  of  60  cycles.  Below  25 
horse-power  the  voltage  commonly  used  is  220,  but  above 
that  power  440  volt  motors  are  usually  adopted.  For 
primary  distribution,  66,000  and  44,000  volts  is  common 
practice  over  extensive  districts,  and  there  are  a  few  large 
pumping  plants  taking  power  direct  from  such  primary 
lines.  The  transformer-room  equipment  is,  however,  very 
complicated  and  expensive,  consequently  most  pumping 
installations  of  moderate  size  should  be  designed,  if  possible, 
to  receive  current  at  2,200  volts,  the  usual  plan  being  for 
the  plant  to  own  the  necessary  transformers  to  step  down 
this  voltage  to  that  of  the  motors,  current  being  measured 
on  the  low-tension  side. 

Below  50  horse-power  ordinary  "squirrel-cage"  induc- 
tion motors  are  commonly  used,  but  above  that  power 
"slip-ring"  induction  motors  with  starting  rheostats  should 
invariably  be  employed,  owing  to  the  excessive  starting 


184  PEACTICAL  IRRIGATION  AND   PUMPING 

current  required  by  the  "  squirrel-cage "  type  in  large  sizes. 
Where  a  large  number  of  induction  motors  are  on  a 
system,  operating  conditions  frequently  require  the  power 
company  to  insist  on  the  adoption  of  synchronous  motors 
in  plants  of  large  size.  Such  motors  have  desirable 
characteristics  for  pumping-plant  operation,  but  require 
special  starting  apparatus,  which  makes  them  less  conveni- 
ent than  an  induction  motor,  and  more  expensive. 

As  to  make,  there  is  but  little  difference  between  small- 
size  induction  motors  of  different  manufacturers,  the  chief 
consideration  being  one  of  sufficient  provision  for  ventila- 
tion. It  is  of  importance,  therefore,  with  any  make,  that  in 
locating  motors  in  the  plant,  they  be  placed  where  there  is 
ample  air  circulation,  avoiding  corners  and  small,  boxlike 
shelters,  etc.  Although  induction  motors  stand  severe 
abuse  they  sometimes  burn  out  through  being  too  heavily 
overloaded  and  through  prevention  of  air  circulation  by 
accumulations  of  oil-laden  dust  on  the  coils  and  in  the 
ventilating  ducts. 

As  to  whether  the  motor  should  be  direct-  or  belt- 
connected  to  the  centrifugal  pump,  there  is  some  chance 
for  argument.  It  is  sometimes  impossible  to  get  the  correct 
speed  when  using  a  direct-connected  small  stock  pump  and 
motor,  and  to  get  this  a  belt-connected  set  is  the  only  solu- 
tion. A  belt,  however,  is  a  constant  source  of  trouble, 
expense,  and  energy  loss.  These  are  completely  avoided 
in  the  direct-connected  sets. 


CHAPTER  XIV 

THE   CENTRAL   STATION  PUMPING  PLANT 

Locations   Suitable   for   Central    Station    Plants. — In 

various  parts  of  the  West  are  to  be  found  large  tracts  of 
land  in  every  way  suitable  for  agriculture,  but  too  remote 
from  surface  streams  to  make  gravity  irrigation  possible. 
Not  infrequently  such  tracts  are  found  to  overlie  a  sub- 
terranean water  supply  of  sufficient  magnitude  and  at  such 
depth  as  to  make  it  possible  to  irrigate  all  or  a  part  of  the 
tract  by  pumping. 

Such  tracts  are:  The  country  surrounding  Portales, 
N.  M.,  part  of  the  Estancia  and  Mimbres  Valleys  of  New 
Mexico,  the  Santa  Clara  Valley,  Arizona;  the  Riverside 
district  and  the  San  Joachim  and  Sacramento  Valleys  of 
California;  the  Willamette  Valley,  Oregon,  the  Valley  of  the 
Arkansas  in  Kansas  and  Colorado,  and  various  others. 
Where  topographic, hydrographic, agricultural,  and  economic 
conditions  all  favor  the  development  of  such  sections  or  tracts 
by  pumping,  it  is  generally  recognized  as  probable,  at  least, 
that  much  the  cheaper  and  more  economical  scheme  of  rec- 
lamation is  by  a  series  of  pumping  plants  scattered  over 
the  tract,  each  driven  by  power  generated  at  a  central  plant 
rather  than  the  same  number  of  individual  plants,  each 
generating  power  by  a  small  engine,  perhaps  very  wasteful 
of  fuel.  At  the  central  plant  large  power  units  being  used, 
advantage  may  be  taken  of  th"e  most  up-to-date  and  eco- 
nomical machinery  and  thus  power  may  be  generated  and 
distributed  to  the  separate  plants  at  considerably  less  than 
it  would  cost  the  individual  owner  to  generate  it  himself. 

185 


1 86  PRACTICAL  IRRIGATION  AND  PUMPING 

Conditions  Governing  Feasibility. — The  feasibility  of 
such  a  plant  depends  upon  a  number  of  conditions,  of 
which  we  may  mention  the  following: 

(a)  Adequacy  and  chemical  character  of  water  supply. 

(b)  Depth  of  water  supply  and  probable  total  head  to 

be  pumped  against. 

(c)  Suitability  of  tract  for  agricultural  purposes. 

(d)  Shipping  and  marketing  facilities. 

(e)  Size  and  shape  of  tract  as  governing  cost   of  dis- 

tribution lines  and  transmission  losses. 

(f)  Ownership  of  tract. 

(g)  Possibilities   of    co-operation   in   case   of   private 

ownership  of  land  and  desirability  of  local 
ownership  and  control. 

(h)   Fuels  obtainable  and  price  delivered. 

(i)  Possibility  of  utilizing  power  at  times  other  than 
during  pumping  season,  e.g.,  beet  sugar  and 
canning  industries,  city  light  and  power,  inter- 
urban  transportation,  general  manufacturing, 
and  other  purposes  requiring  power. 

It  will  be  seen  at  once  from  a  consideration  of  these 
conditions  that  a  decision  as  to  the  feasibility  of  the  cen- 
tral pumping  plant  must  be  based  upon  a  broad  study  of  a 
large  number  of  more  or  less  closely  related  subjects,  all  of 
which  have  an  important  bearing  upon  the  feasibility  of 
such  a  project.  It  is,  therefore,  not  a  matter  to  be  decided 
offhand,  and  parties  interested  in  the  development  of  such 
a  project  should  call  to  their  aid  the  services  of  a  compe- 
tent engineer, -who  is  familiar  not  only  with  the  engineering 
features  of  such  a  scheme,  but  who  also  understands  thor- 
oughly the  irrigation  side  of  the  problem.  He  should  be 
required  to  inquire  carefully  into  all  sources  of  information 
and  present  a  report  covering  essentially  the  points  men- 


THE   CENTRAL   STATION  PUMPING  PLANT  187 

tioned  on  page  186,  besides  giving  his  opinion  as  to  the 
practicability  and  feasibility  of  the  project.  Upon  such 
a  report,  if  favorable,  local  parties  will  be  warranted  in 
vigorously  furthering  the  scheme  and  with  such  a  report, 
if  it  is  desirable  or  necessary  to  introduce  outside  capital, 
there  is  much  greater  chance  of  interesting  the  careful  in- 
vestor or  capitalist  than  by  setting  before  him  a  mass  of 
glittering  generalities,  guesses,  and  assumptions. 

(a)  Adequacy  of  Supply. — Naturally  the  first  question 
of  importance  arising  is  as  to  the  source  of  supply  and  its 
adequacy  to  the  purposes  of  the  project.  Where  a  surface 
stream  is  to  be  used,  simple  measurements  and  records 
of  stream  flow  will  give  the  desired  information  as  to 
available  supply,  but  where  an  underground  supply  is  to 
be  developed  the  matter  is  largely  mere  conjecture  when 
considering  the  possible  demands  for  a  large  acreage. 
Existing  wells  in  the  tract,  if  any,  should  be  investigated, 
and,  if  possible,  their  maximum  capacity  ascertained.  If 
no  suitable  wells  are  available,  test  wells  should  be  sunk 
and  such  temporary  machinery  be  installed  as  will  enable 
a  test  to  be  made  not  only  of  the  flow,  but  of  the  draw-down 
at  various  flows,  and  of  the  saline  ingredients  at  various 
depths.  If  the  saline  contents  exceed  4,000  parts  in  1,000,- 
ooo,  it  is  doubtful  if  the  water  could  be  used  with  success 
in  irrigation.  In  the  event  of  an  excess  of  salts  in  the 
water  at  one  level,  it  is  frequently  possible,  by  going  deeper,  j 
to  strike  other  strata  in  which  the  salty  ingredients  are 
so  small  as  to  be  harmless. 

Regarding  the  total  amount  of  water  required  over  the 
tract  at  any  given  time,  it  will  be  found  an  extremely  dif- 
ficult matter  to  arrive  at  any  very  satisfactory  estimate. 
If  the  tract  be  divided  up  into  a  large  number  of  small 
holdings  and  only  one  crop  is  grown,  it  is  not  unlikely, 
unless  a  very  unusual  degree  of  co-operation  and  organi- 


1 88  PRACTICAL   IRRIGATION  AND   PUMPING 

zation  exists,  that  all  will  require  water  simultaneously, 
making  a  very  serious  draft  upon  the  underground  supply 
and  a  severe  demand  upon  the  power  station,  not  only 
by  reason  of  the  large  number  of  pumps  in  operation  at 
the  same  time,  but  also  because  the  draw-down  is  likely 
to  be  increased  considerably,  shortly  after  pumping  be- 
gins. Diversified  crops  and  a  centralized  distribution, 
whereby  the  periods  of  demand  for  power  will  be  more 
constant,  is  something  which  is  imperative  in  economical 
operation  of  a  central  power  station  for  pumping  and  is  a 
matter  which  should  be  well  understood  by  all  interested 
parties. 

The  value  of  diversified  crops  in  increasing  the  yearly 
load  factor  can  best  be  shown  by  an  example.  Let  us 
assume  an  area  of  10,000  acres  planted  in  crops  as  follows: 

3,000  acres  in  alfalfa, 

3,000  acres  in  orchard, 

3,000  acres  in  small  grains,  etc., 

"i,ooo  acres  in  melons  and  truck  gardens. 

These  areas  may  be  assumed  as  divided  into  a  large 
number  of  small  holdings,  but  since,  under  ordinary  cir- 
cumstances, each  crop  over  the  entire  district  will  need 
water  simultaneously,  it  is  probably  equivalent  to  a  single 
holding.  This  statement  may  need  some  modification  in 
practice,  since  not  always  will  the  judgment  as  to  a  crop's 
moisture  requirements  be  unanimous.  Among  the  more 
skilful  and  experienced  irrigators  there  is,  however,  sur- 
prising unanimity  of  opinion  as  to  the  time  for  irrigation, 
as  has  been  proven  time  and  again  in  the  management 
of  irrigation  enterprises  to  the  dismay  of  managers,  who 
for  some  reason  might  happen  to  be  ill-prepared  for  large  and 
sudden  demands  for  water.  Upon  the  above  assumption, 
however,  we  may  construct  the  following  diagrams,  which 
represent  days  of  the  irrigation  system  on  the  horizontal 


THE   CENTRAL   STATION  PUMPING  PLANT 


189 


axis  and  acre-feet  on  the  vertical  axis.  Sections  i  to  4  rep- 
resent the  individual  weekly  requirements  of  the  different 
crops,  while  section  5  represents  the  total  amount  to  be 
supplied  the  entire  area  from  week  to  week. 

As  will  be  seen  from  the  diagram,  the  total  water 
requirement  for  the  entire  acreage  under  diversified  crops 


£•00 

£ioo 

r^\ 

r 

I 

\( 

^ 

E 

-^ 

/LUX 

\ 

if 

: 

\ 

1 

km  . 

I 

41 

: 

•  • 

2ioo 


^200 


ALFALFA 


ORCHARDS 


GRAINS 


MELONS,  TRUCK  GARDENS 


500 

\  \ 

/ 
f 

\ 

.400 

*•  ->. 

\ 

\ 

\ 

/* 

/" 

"^i  \ 

\ 

S 

\ 

• 

r~ 

'^\§  \ 

i 

\ 

-<200 
100 

1 

1 

;   J 

E: 

^ 

"Ts 

^ 

CSS 

4i-/ 

i 

' 

/ 

8   12  16  20   24  28   32  3o   10  41  48   52    56  60  64   68    72   76  80  84   88   92  96  lOODays 
SUMMATION  OF  ENTIRE  DEMAND 
OF  DISTRICT^ 

DIAGRAM  24 


is  much  less  irregular  than  the  individual  requirement  of 
any  particular  crop,  and  the  maximum  total  amount  re- 
quired, which  governs  the  maximum  power  requirement 
and  therefore  the  size  of  the  central  station  equipment, 
is  1 6  per  cent,  less  than  though  the  entire  area  was  in 
alfalfa.  Such  diagrams,  compiled  from  the  best  available 


I  go  PRACTICAL  IRRIGATION  AND  PUMPING 

information  as  to  number  of  irrigations  and  periods  between 
same  and  the  probable  water  requirement  for  such  crops 
as  may  probably  be  grown  successfully  in  the  district  in 
question,  should  always  be  used  to  assist  in  forming  an 
intelligent  estimate  of  the  total  water  requirement,  and, 
therefore,  the  probable  power  requirement  when  the  head 
is  determined. 

(b)  Head. — We  have  already  considered  the  question  of 
draw-down  and  of  static  and  friction  head,  so  that  when 
the  average  depth  to  water  is  known,  it  may  be  possible 
to  estimate  with  some  degree  of  accuracy  that  total  head 
against  which  the  water  must  be  pumped.  This  will,  of 
course,  be  an  average  for  the  district,  since  the  ground- 
water  plane  being  practically  level,  the  static  head  will 
naturally  vary  with  the  topography  and  the  total  head  on 
some  quarter  sections  will  be  very  much  different  from 
that  on  others  in  the  same  section,  particularly  in  a  rolling 
country. 

Now  arises  the  important  question  as  to  what  crops 
may  be  grown  with  profit,  using  water  pumped  through 
the  average  head  just  estimated.  This  is  really  the  crux 
of  the  whole  matter,  and  involves  in  its  solution  not  only  a 
fair  estimate  of  yields,  producing  costs,  shipping  costs,  and 
market  rates,  but  also  an  approximately  correct  idea  of  the 
cost  of  producing  and  distributing  electric  power  over  the 
area  in  question. 

The  best  way  of  attacking  this  problem  is  to  determine 
first  the  approximate  cost  of  delivering  an  acre-foot  of 
water  at  the  surface  for  an  acreage  of  a  specified  amount, 
using  an  average  power  cost,  and  taking  into  account  all 
legitimate  expenses  chargeable  to  pumping  plant.  In  es- 
timates and  calculations  on  this  problem,  it  should  be 
considered  from  the  standpoint  of  the  individual  owner  of 
small  means,  who  is  the  one  most  likely  to  be  attracted 


THE   CENTRAL   STATION  PUMPING  PLANT  IQI 

by  the  irrigation  pumping  proposition.  This  problem  has 
been  analyzed  in  Chapter  XI,  headed  "The  Question  of 
Cost  and  Profit  on  a  Small  Farm  Irrigated  by  Pumped 
Water." 

(c)  Suitability  of  Tract   for  Agricultural  Purposes. — 
This  had  best  be  determined,  if  in  an  absolutely  new 
country,  by  the  character  of  the  native  vegetation  and  by 
the  depth  and  physical  character  of  soil  as  determined  by 
borings  and  test  pits  in  different  localities.     Samples  of 
the  soil  should  be  sent  to  the  State  Agricultural  Experiment 
Station  for  chemical  analysis,  and  an  opinion  obtained  as 
to  its  value  for  agricultural  purposes,  while  if  time  and 
opportunity  permit  it  may  be  well,  also,  to  have  an  agri- 
cultural expert  go  over  the  ground  and  give  his  opinion  as 
to  its  suitability  for  the  proposed  purpose.    In  case  agri- 
culture of  any  kind  has  been  carried  on  in  the  tract  or 
upon  adjoining  tracts  of  like  character  not  too  far  distant 
to  present  materially  different  climatic  and  soil  conditions, 
it  will  be  necessary  to  obtain,  if  possible,  full  information 
as  to  feasible  crops,  yields,  action  of  soil  under  irrigation, 
i.e.,  whether  easy  or  difficult  to  irrigate,  etc.    The  opinion 
of  experienced  irrigators  on  the  tract  or  in  vicinity  should 
be  given  great  weight,  usually,  on  general  questions  of 
methods  of  irrigation. 

(d)  Shipping    and  Marketing  Facilities. — A  very  im- 
portant consideration  in  connection  with  the  success  of  any 
project,  except  where  it  is  so  fortunately  located  as  to  be 
within  hauling  distance  of  some  market  big  enough  to 
absorb  the  entire  product,  is  evidently  the  provision  for 
getting  the  product  to  market  cheaply  and  quickly.    In  the 
case  of  perishable  products,  like  melons  and  garden  veg- 
etables, some  well-organized  shippers'  association  is  neces- 
sary to  handle  the  product  successfully,  and  of  course  it 
goes  without  saying  that,  in  such  cases,  the  tract  must 


1 92  PRACTICAL  IRRIGATION  AND  PUMPING 

have  railroad  facilities.  A  wagon  haul  of  more  than  3  miles 
is  usually  fatal  to  melons  and  a  haul  of  as  low  as  5  miles 
with  alfalfa  will  pare  down  the  profits  materially.  It  is 
well,  therefore,  to  canvass  the  question  of  markets  and 
shipping  facilities  pretty  thoroughly  in  a  report,  and  state 
what  market  is  available  or  may  be  developed  and  how 
reached.  This  matter,  while  more  one  of  economics  than 
engineering,  cannot  be  neglected  by  any  engineer  who 
attempts  to  present  a  fair  and  unbiased  report  upon  the 
merits  of  an  irrigation  enterprise,  either  for  his  clients  or 
for  the  general  public.  The  history  of  the  West  is  replete 
with  instances  where  engineers  have  considered  merely  the 
engineering  features  of  irrigation  enterprises,  and  have 
ignored  the  equally  important  question  of  whether  it  will 
probably  pay  their  clients  to  finance  the  undertaking,  and 
the  general  public  to  attempt  to  farm  the  lands. 

(e)  Size  and  Shape  of  Tract. — Where  electricity  is  to 
be  generated  and  transmitted  from  a  central  station,  it  is 
of  very  considerable  importance  that  the  points  at  which 
the  power  is  to  be  used  shall  be  compactly  grouped.    This 
requires,  first,  that  the  lands  irrigated  shall  preferably  be  in 
one  body  and  not  in  isolated  or  individual  tracts ;  secondly 
that  the  tract  shall  not  be  in  the  shape  of  a  long,  narrow 
strip.     The  reason  for  this,  obviously,  is  that  the  more 
closely  grouped  the  pumping-plants  are,  and  the  closer  they 
are  to  the  power-station,  the  less  is  going  to  be  the  cost  of 
transmission  lines  and  the  less  the  transmission  losses. 

(f)  Ownership   of    Tract— Central    station    pumping 
plants  may  be  financed  and  installed  in  one  of  several  ways. 
First,  by  the  co-operation  of  a  group  of  farmers  who  actually 
own  the  land.    In  this  case  the  number  of  farmers  must  be 
sufficient,  the  land  controlled  sufficient  in  acreage,  and  suf- 
ficiently contiguous  to  make  central  station  pumping  evi- 
dently worth  while,  by  which  we  mean  that  unless  the 


THE   CENTRAL   STATION  PUMPING  PLANT  193 

acreage  combined  is  in  excess  of  1,000  acres  in  one  body, 
a  central  station  proposition  is,  at  least,  doubtful.  Second, 
the  scheme  may  be  promoted  by  a  company  which  en- 
deavors to  furnish  power  to  individual  pumping-plant 
owners,  charging  upon  the  basis  of  the  power  used.  In  this 
case,  the  same  caution  must  apply  as  has  been  found  neces- 
sary in  the  promotion  of  gravity  irrigation  schemes,  namely, 
that  the  only  safe  course  for  any  irrigation  development 
proposition  is  to  own  at  least  one-half  of  the  land  to  which 
the  water  is  to  be  applied,  making  profits  sufficient  to  pay 
for  the  initial  investment  out  of  the  rise  in  the  value  of  the 
land  to  which  water  may  be  applied.  The  company  which 
has  no  load  other  than  a  pumping  load  and  which  depends 
for  its  revenues  solely  upon  the  sale  of  power  will  soon  find 
itself  in  the  same  financial  condition  as  have  many  irriga- 
tion companies  which  put  large  sums  of  money  into  dams, 
reservoirs,  and  distribution  systems,  and  merely  sold  water 
to  irrigators  at  so  much  per  acre-foot.  Very  few,  if  any, 
such  enterprises  paid  interest  on  the  capital  invested. 
The  only  entirely  satisfactory  basis  upon  which  a  company 
may  undertake  a  central  station  pumping  project,  is  first 
to  acquire  at,  say,  not  over  $15  per  acre,  a  suitable  tract  of 
dry  land,  and  develop  same  ready  for  occupancy  and  irri- 
gation by  prospective  farmers  to  whom  it  is  sold  on  a 
basis  of  double  or  treble  the  original  cost  under  a  contract 
providing  for  payment  in  a  term  of  years,  and  providing 
further  that  the  central  power-station  property  shall 
eventually  pass  into  the  control  of  the  landholders.  Where, 
however,  the  pumping  load  is  merely  incidental  or  additional 
to  the  existing  load,  or  that  which  it  is  proposed  to  develop, 
it  is  not  so  essential  for  the  company  to  own  a  tract  of  land, 
but,  nevertheless,  it  is  always  a  wise  precaution. 

(g)   Possibilities  of  Co-operation,  etc. — Where  a  com- 
pany already  established  proposes  to  furnish  power  to  the 


194  PRACTICAL  IRRIGATION  AND  PUMPING 

owners  of  lands  for  pumping  purposes,  it  will  be  found 
essential  in  more  or  less  extensive  projects  to  draw  up  con- 
tracts in  which  the  time  of  day  during  which  power  will  be 
supplied  for  pumping  is  expressly  agreed  upon.  It  will 
also  be  essential  to  enlist  the  co-operation  of  these  owners 
to  reduce  the  peak  load  by  dividing  themselves  into  dis- 
tricts, each  of  which  will  use  power  when  irrigation  is 
needed,  on  certain  days  of  the  week,  thus  avoiding  an 
overlapping  of  demands,  which  it  might  exceed  the  over- 
load capacity  of  the  central  plant  to  supply,  and  which 
would  invariably  result  in  dissatisfaction  among  the 
pumping-plant  operators,  and  an  unfortunate  resentment 
against  the  company. 

(h)  Fuels  and  Price.— The  question  of  fuel  is  an  im- 
portant one  in  connection  with  central  station  pumping, 
and  is  a  matter  to  be  considered  carefully  in  deciding  upon 
the  most  suitable  central  station  equipment.  The  various 
fuels  have  been  discussed  previously,  as  well  as  have  the 
prime  movers  in  which  they  would  be  used,  hence  it  is  un- 
necessary to  more  than  mention  here  the  connection  of  the 
fuel  question  with  the  more  general  study  of  the  feasibility 
of  a  central  station  for  pumping. 

Where  water  power  may  be  developed  within  50  miles 
of  the  irrigation  project  this  may  be  by  far  the  more 
economical  power  to  use  under  conditions  favoring  easy 
construction  of  the  electric  generating  plant. 

Pumping  Season. — The  greatest  danger  to  the  success 
of  an  electrical  pumping-plant  project  is  in  the  brevity  of  the 
season  during  which  power  for  pumps  is  required,  and 
excessive  peak  loads.  From  90  to  105  days  of  the  year  is 
the  period  during  which  pumps  may  be  run  for  irrigation 
purposes  and  except  under  the  most  skilful  management, 
even  with  the  most  helpful  co-operation  of  the  plant  oper- 
ators, the  load  factor  during  these  90  to  105  days  is  likely 


THE   CENTRAL   STATION  PUMPING  PLANT  195 

to  be  ioo  per  cent.,  that  is,  the  demand  for  power  may  at 
times  (when  every  one  is  irrigating)  be  equal  to  the  com- 
bined horse-power  of  every  plant  in  the  project.  If,  for 
instance,  there  were  40  plants,  each  requiring  25  horse- 
power, the  total  load  might  be  about  1,000  horse-power  for 
most  of  the  time,  or,  as  shown  by  Diagram  24  on 
page  189,  there  would,  even  with  diversified  crops,  be  occa- 
sions for  a  week  at  a  time  when  the  entire  series  of  plants 
would  be  in  operation.  Thus  we  have  a  condition  which 
every  experienced  power  engineer  seeks,  if  possible,  to 
avoid,  namely,  a  plant  of  large  station  capacity,  but  of 
exceeding  low  yearly  load  factor.  If  the  plant  is  used  for 
irrigation  alone  it  will  stand  idle  for  over  two-thirds  of  the 
year.  Common  business  prudence,  therefore,  suggests  that 
some  use  be  found  for  the  plant  during  the  remainder  of 
the  year.  In  well-settled  localities  there  will  likely  be 
demand  for  power  in  lighting,  in  power  purposes  on  the 
farms,  and  possibly  in  industrial  enterprises  of  various 
kinds,  and  in  street  or  interurban  railway  service.  The 
lighting  load  is  one  which  will  not  necessarily  add  to  the 
peak  load  during  the  pumping  season,  but  it  must  be 
noted  that  industrial  power  and  railway  requirements  will 
add  to  the  maximum  capacity  of  the  plant,  since  the  re- 
quirement is  likely  to  be  constant  throughout  the  year. 
The  really  desirable  kind  of  load  to  develop  is  one  which 
is  not  coincident  with  the  pumping  load,  and  this  may  be 
found  in  such  service  as  supplying  power  for  beet-sugar 
manufacture  and  canning  factories.  Indeed,  it  would  seem 
a  very  desirable  phase  of  the  work  of  a  beet-sugar  factory 
to  utilize  its  boiler  plant  during  the  period  in  which  it 
would  otherwise  be  idle  in  furnishing  power  for  pumping, 
lighting,  and  general  power  purposes,  if  situated  in  a  region 
where  water-power  is  not  available,  and  where  lands  desir- 
able for  beet  raising,  but  above  existing  canals,  could  yet 


196  PRACTICAL  IRRIGATION  AND  PUMPING 

be  irrigated  by  pumps  driven  by  power  generated  at  the 
factory.  The  same  observation  holds  in  regard  to  the 
usual  canning  factory  or  any  concern  using  steam  and 
power  in  large  quantities  for  only  a  brief  period  each  year. 
In  the  Snake  River  Valley  where  hydro-electric  power 
is  used  in  large  amounts  for  pumping  from  the  river  and 
canals,  the  power  companies  make  a  special  rate  for 
heating  of  residences  and  buildings  by  electricity,  thus 
providing  a  source  of  income  during  the  fall  and  winter. 


CHAPTER  XV 

WINDMILLS 

The  Field  of  the  Windmill  in  Irrigation. — Any  discus- 
sion of  pumping  for  irrigation  would  be  incomplete  without 
some  reference  to  the  use  of  windmills.  Although  wind- 
mills cannot  possibly  be  regarded  as  feasible  or  economical 
of  use  for  the  areas,  quantities  of  water,  and  heads  con- 
templated by  our  previous  discussion,  the  windmill  has  a 
very  useful  field  and  is  a  most  important  feature  of  certain 
classes  of  Western  agriculture.  Its  most  conspicuous 
service  in  recent  years  has  been  in  the  aid  of  dry-farming; 
indeed,  it  seriously  may  be  doubted  if  without  the  small 
truck  or  garden  patch  and  the  domestic  water  supply  made 
possible  by  the  windmill,  even  a  bare  existence  would  have 
been  the  reward  of  those  hardy  pioneers  who  have  shown 
up  the  possibilities  of  dry  farming.  It  is  an  unquestioned 
fact,  as  proved  by  the  experience  of  all  who  have  tried  it, 
that  to  make  life  endurable  on  the  dry  farm  and  to  have 
some  means  of  tiding  over  the  unusually  dry  and  unpro- 
ductive years,  there  must  be  some  independent  means  of 
water  supply  sufficient  to  irrigate  three,  and  preferably  five 
or  seven,  acres  of  truck  garden  and  alfalfa.  The  products 
of  such  an  acreage  may  be  the  sole  support  of  the  dry 
farmers'  family  and  stock  during  those  off  years  which 
must  be  expected,  however  firm  may  be  the  prevailing 
belief  as  to  a  permanent  change  in  climate. 

For  the  development  of  the  water  supply,  some  have 
installed  power-pumping  plants,  but  the  majority  favor  a 
windmill  plant,  because  of  its  simplicity  and  apparent 
small  operating  expense.  Another  important  field  of  use- 

197 


198  PRACTICAL  IRRIGATION  AND  PUMPING 


fulness  for  the  windmill  in  irrigation  is  in  connection  with 
the  development  of  small  orchard  tracts  in  the  suburbs  of 
many  of  the  Western  cities.  Here  suitable  tracts  may 
frequently  be  acquired  on  the  mesas  or  benches  adjacent 
to  the  town,  which  are  not  supplied  by  high-line  canals, 
and  yet  where  a  water  supply  may  be  developed  within  a 
depth  of  100  feet.  Such  tracts  possess  the  evident  advan- 
tage of  convenience  to  market,  and  many  men  are  trying 
the  experiment  of  putting  small  tracts  of  5  to  10  acres  into 
orchards  of  peach,  apple,  pear  trees,  etc.,  irrigating  by 
water  pumped  by  windmill.  Wind  power  is  used  almost 
exclusively  for  pumping  the  water  supply  of  stock  on  the 
great  ranges  of  the  Southwest.  This  is  a  development  of 
the  last  10  or  15  years,  and  has  enabled  cattle  to  be  grazed 
on  vast  areas  formerly  untouched  because  of  distance  from 
nearest  water  hole  or  surface-water  supply.  The  discovery 
of  water  beneath  portions  of  the  great  plains  of  Texas,  and 
other  sections  long  considered  hopelessly  dry,  with  the 
subsequent  rapid  dry-farming  development,  is  the  result  of 
the  successful  attempt  of  cattlemen  to  erect  windmills  for 
stock  watering,  and  thus  extend  the  ranges.  Altogether, 
it  may  be  said  that  wind  power  offers  a  very  interesting 
and  possibly  the  ultimate  solution  of  the  problem  of  devel- 
oping the  agricultural  possibilities  of  the  great  plains 
country  by  pumping.  Undoubtedly,  as  fuel  increases  in 
price,  as  it  will,  at  an  increasing  rate  as  the  years  go  on, 
manufacturers  will  be  justified  in  introducing  improve- 
ments in  wind  engines,  which  will  increase  their  power  and 
general  suitability  to  the  requirements  of  pumping,  these 
improvements  now  being  delayed,  owing  to  the  impossi- 
bility of  constructing  windmills  of  the  power  of  small  gaso- 
line engines,  which  will  anywhere  near  approach  the  price 
of  the  latter. 

Kind  of  Mills. — It  is  not  our  purpose  to  enter  into  any 


WINDMILLS  199 

technical  discussion  of  windmills,  and  it  will  suffice  merely 
to  mention  some  of  the  more  important  types  and  classes  of 
mills  as  respects  their  structure. 

Size. — Windmills  are  rated  according  to  the  diameter  of 
the  wind  wheel,  which  in  standard  American  machines  may 
vary  from  8  to  16  feet  by  intervals  of  2  feet.  Sizes  larger 
than  1 6  feet  are  in  use  by  railroad  companies,  and  in  some 
localities,  as,  for  instance,  in  certain  parts  of  California, 
very  large  home-made  wheels  upward  of  25  feet  in  diameter 
are  in  use.  The  Dutch  type  of  mill  has  a  four-vane  wheel 
of  very  large  diameter,  but  there  are  only  one  or  two 
examples  of  this  type  in  this  country,  and  it  is  of  no  com- 
mercial importance  whatever.  As  to  the  material,  the  more 
common  examples  of  modern  windmills  have  galvanized 
pressed-steel  vanes  in  the  wheel,  but  there  are  also  on  the 
market  very  serviceable  mills  with  wooden  vanes.  Under 
modern  methods  of  construction,  using  light  structural 
steel  shapes  and  pressed-steel  vanes,  etc.,  there  is  no  reason 
why  a  steel  mill  cannot  be  made  as  light  as  the  wooden 
type,  besides  being  stronger  and  more  durable. 

Governing. — In  order  to  prevent  the  mill  from  being 
blown  down  in  high  winds,  which  would  happen  if  the  full 
sail  area  of  the  wheel  were  opposed  to  the  wind  at  all 
times,  various  schemes  of  governing  have  been  adopted  by 
different  makers.  The  most  common  scheme  is  to  turn  the 
wheel  with  its  edge  to  the  wind  in  high  velocities  by  either 
a  governing  vane  which  functions  when  the  air  pressure  on 
its  area  exceeds  a  predetermined  limit  as  measured  by  an 
opposed  spring;  or  in  one  make  of  mill  the  axis  of  the  wheel 
is  set  eccentrically  to  the  vertical  axis  of  rotation,  and  the 
air  pressure  on  the  wheel  area  itself  forces  the  whole  head 
to  rotate  on  the  vertical  axis  against  the  opposition  of  the 
tail  as  determined  by  a  spring,  the  tension  of  which  can  be 
adjusted.  Another  method  is  one  in  which  the  vanes  are 


200  PRACTICAL   IRRIGATION  AND   PUMPING 

rotated  about  their  long  axis,  so  as  to  oppose  merely  their 
edges  to  high  winds,  while  in  still  another  scheme,  the  vanes 
are  hinged  at  the  periphery  of  the  wheel,  and  in  high  winds 
the  vanes  move  into  a  position  with  their  axes  more  or  less 
closely  parallel  with  the  direction  of  the  wind.  Obviously 
in  the  last  two  cases  the  plane  of  the  wheel  remains  per- 
pendicular to  the  direction  of  the  wind,  and  the  mill  is  not 
usually  provided  with  a  tail  or  rudder. 

Another  important  difference  between  types  of  mills  is 
in  respect  to  the  manner  in  which  the  power  is  transmitted. 
With  some  mills  the  power  is  transmitted  to  a  pump  rod 
directly  by  a  pitman  connected  to  a  crank  on  the  main 
shaft  of  the  wind  wheel.  In  another  class,  known  as  geared 
mills,  the  pump  rod  is  attached  to  a  pitman  connected  to  a 
crank  pin  on  a  gear  which  meshes  with  a  pinion  on  the 
wind-wheel  shaft.  The  usual  gear  ratio  is  from  3  or  4  to  i, 
thus  making  the  number  of  pump  double  strokes  from 
one-third  to  one-fourth  the  number  of  revolutions  of  the 
wind  wheel. 

In  another  type  of  mill,  the  wind  wheel  is  connected  by 
a  bevel  gear  and  pinion  to  a  vertical  shaft,  which  by  means 
of  a  second  set  of  bevel  gears  at  the  base  of  the  tower  may 
transmit  power  to  a  horizontal  shaft  to  which  the  pump- 
ing machinery  may  be  attached.  This  is  known  as  a  power 
mill,  and  is  useful  for  other  purposes  than  pumping,  though 
there  is  some  loss  of  power  through  friction  in  the  two  sets 
of  gearing  necessary,  which  is  avoided  with  the  pump- 
rod  types. 

The  Selection  of  a  Mill. — It  is  useless  to  make  many 
specific  recommendations  concerning  the  selection  of  a 
mill,  since  it  is  to  be  expected  that  the  makers'  statements 
in  advertising  literature  very  frequently  will  be  taken 
without  the  necessary  " grain  of  salt/'  and  just  as  often  a 
mill  will  be  bought  upon  its  reputation  or  upon  the  en- 


WINDMILLS  2OI 

dorsement  of  a  neighbor.  We  may,  however,  lay  down 
these  general  rules,  which  should  govern  one  in  buying  any 
mill. 

(1)  POWER  OF  MILL.— A  mill  is  wanted    that  will 
deliver  the  maximum  possible  quantity  of  water  pumped 
from  a  predetermined  depth  with  such  wind  conditions  as 
prevail  in  the  given  locality. 

(2)  GOVERNING. — A  mill  is  wanted  which  will  govern 
properly  in  high  winds  with  a  minimum  of  personal  atten- 
tion. 

(3)  STRENGTH  AND  DESIGN. — A  mill  is  wanted    in 
which  the  parts  are  of  ample  strength,  but  not  necessarily 
heavy  and  massive. 

(4)  BEARINGS  AND  OILING  DEVICES.— A  mill  is  wanted 
which  has  ample  bearings  properly  fitted  and  provided  with 
oiling  devices  of  sufficient  capacity  and  such  type  that  the 
mill  will  not  have  to  be  oiled  oftener  than  once  a  month. 

(5)  PUMP  CYLINDER. — A  pump  cylinder  is  wanted  of 
capacity  that  will  load  the  mill  properly  and  which  is  so 
designed  and  made  of  such  material  as  will  give  a  maximum 
length  of  service  with  the  least  wear  of  working  barrel  and 
valves. 

The  points  above  cover  the  general  specifications  of 
importance  to  consider  in  the  purchase  of  a  mill  as  regards 
the  size  of  wheel  and  the  pump  cylinder,  together  with  the 
design  and  construction  of  the  essential  working  parts. 
Many  windmills  in  standard  sizes  and  prices  are  now  on  the 
market  which  conform  to  the  desired  character  of  construc- 
tion indicated.  When  the  intending  purchaser  has  decided 
upon  the  size  and  type  of  mill  he  needs,  his  only  care  will 
be  to  see  that  he  does  not  buy  a  low-priced  mill  in  which 
the  construction  does  not  conform  to  what  has  come  to 
be  regarded  as  standard. 

Power  of  Mill. — We  have  in  this  matter  many  factors 


2O2 


PRACTICAL  IRRIGATION  AND   PUMPING 


involved  which  it  has  been  the  endeavor  of  numerous 
experimenters  to  discover  and  correlate.  Among  the  pub- 
lished researches  which  concern  the  power  of  wind  wheels, 
we  may  mention  those  of  Wolf,  Perry,  E.  C.  Murphy,  Hood, 
Fargusson,  King,  and  Fuller,  in  this  country,  and  of  Chat- 
ter ton  in  India,  and  Ringelmann  in  France.  The  endeavor 
of  these  various  experimenters  has  been  to  derive  some 
relation  between  the  power  of  a  mill  measured  in  horse- 
power, the  diameter  and  type  of  wheel,  and  the  velocity 
of  the  wind. 

Their  work  has  very  clearly  demonstrated  the  extreme 
complexity  of  the  problem,  but  some  important  facts  have 
been  established  which  have  an  immediate  bearing  upon 
the  practical  problem  of  so  proportioning  the  load  and  size 
of  a  mill  for  a  given  locality  that  the  maximum  possible 
amount  of  work  may  be  accomplished  by  the  mill  in  a 
given  time.  The  first  matter  to  which  attention  should  be 
given  is  the  wind  record  for  the  specific  locality,  or  at  the 
nearest  Weather  Bureau  station  where  records  are  kept. 
Such  a  record  for  Cheyenne,  Wyoming,  taken  from  Farmer's 
Bulletin  394  on  Windmills,  shows  that  v  the  average  wind 
velocities  during  a  period  of  five  years  for  the  months 
April-September,  inclusive,  were  as  follows: 


Hours  per  Month  during  which  the  Wind's  Velocity  per  Hour  was 


Miles'  per  Hour.  .  . 
Hours. 

o  to  5 
209.9 

6-10 
283  6 

11-15 

16-20 
62  ^ 

21-25 

26-3O 

31-35 

36-40 

40  and  oven 

A  similar  record  may  be  obtained  from  any  Weather 
Bureau  observation  office,  and  should  be  obtained  if  a 
study  similar  to  the  following  is  intended  for  a  specific 
locality.  The  following  is  a  table  similar  to  that  above, 
and  gives  results  of  observations  of  wind  velocities  at 


WINDMILLS 


203 


Dodge    City,  Kansas,   for  seven  years,  as  compiled  by 
Mr.  Murphy: 

Hours  per  Month  during  which  the  Wind's  Velocity  per  Hour  was 


Miles  per  hour.  . 
Hours 

oto  5 
140 

6-10 

1  08 

11-15 

157 

16-20 

IOQ 

21-25 
72 

26-30 
-14. 

31  and  over 

22 

The  most  conspicuous  fact  apparent  from  the  above 
tables  is  the  great  preponderance  of  time  during  which 
comparatively  low  wind  velocities  prevail  even  in  so  notably 
windy  a  climate  as  that  of  Wyoming.  It  is  evident,  there- 
fore, that  the  mill  will  be  best  fitted  for  accomplishing  use- 
ful work  which  will  make  use  of  the  low  wind  velocities, 
for,  if  these  can  be  determined,  then  some  estimate  is  possible 
of  the  amount  of  water  which  a  mill  may  pump  in  a  season 
if  the  depth  to  water  and  the  friction  and  hydrostatic  head 
are  known,  as  well  as  the  size  of  the  pump  cylinder. 

The  diagrams  on  page  204,  taken  from  Farmer's  Bul- 
letin 394,  show  certain  characteristics  of  a  1 4-foot 
power  mill. 

The  first  of  these  diagrams  shows  the  most  important 
fact  to  be  noted  in  connection  with  a  study  of  windmills, 
namely,  that  the  horse-power  which  the  windmill  may 
deliver  is  dependent  upon  the  load  placed  on  the  mill. 
Thus  in  Diagram  25,  the  curves  marked  A,  B,  C,  etc., 
correspond  to  what  would  in  effect  follow  a  progressive 
increase  in  the  size  of  pump  cylinder,  where  the  mill  is  used 
for  pumping.  Take,  for  example,  curve  A.  This  would  cor- 
respond to  a  pump  cylinder  of  small  diameter,  so  that  the 
number  of  pounds  of  water  lifted  per  one  stroke  of  pump 
is  small.  It  will  be  noted  that  a  mill  with  this  load  would 
start  in  a  wind  of  about  4  miles  per  hour,  and,  as  the 
wind  velocity  increased,  the  horse-power  output  would 


204 


PRACTICAL  IRRIGATION  AND  PUMPING 


5.5 


14  FT.STEEL  MILL 

POWER  DEVELOPED  AT 
DIFFERENT  LOADINGS 
AND  WIND  VELOCITIES 


6        8       10       12      14      16      18      20      22 

Wind  Velocity  -Miles  per  Hour 


28      30 


DIAGRAM   25 


14  FT.STEEL  MILL 


£60 

l« 

tc   ' 

s 

CO  .. 

£l 


/ 


4        6        8       10      12      14      16      18      20      22      24      26      28      30      32 
Wind  Velocity  —Miles  per  Hour 


DIAGRAM  26 


WINDMILLS  205 

increase  very  slowly.  As  will  be  seen  from  curve  A  in 
Diagram  26,  the  speed  of  the  wheel  would  increase  very 
rapidly  at  this  load.  Refer  now  to  the  curve  marked  H, 
in  both  diagrams.  This  would  correspond  to  a  very  much 
larger  pump  cylinder  and  a  greater  weight  of  water  lifted 
each  pump  stroke.  As  will  be  seen  in  Diagram  26,  the 
mill  would  not  start  with  this  load  until  the  wind  had 
attained  a  velocity  of  nearly  20  miles  per  hour,  but  a  slight 
increase  in  wind  velocity  would  be  accompanied  by  a  very 
rapid  increase  in  delivered  horse-power,  so  that  at  a  veloc- 
ity of  26  miles  per  hour  the  mill  thus  heavily  loaded  would 
deliver  nearly  seven  times  the  horse-power  of  the  same  mill 
loaded  as  in  the  first  case  and  at  the  same  wind  velocity. 
The  speed  of  the  mill  would  also  be  40  revolutions  less  per 
minute  for  the  heavier  load.  These  diagrams,  therefore, 
illustrate  a  very  important  fact  or  principle,  viz.,  that  the 
power  output  of  a  mill  in  a  given  wind  velocity  varies  with 
the  load  upon  it  and  that  at  the  higher  velocities  of  wind 
the  heavily  loaded  mill  gives  a  greater  horse-power  at  a 
more  desirable  speed  for  pumping  purposes.  On  the  other 
hand,  the  heavily  loaded  mill  will  deliver  no  power  what- 
ever in  moderate  winds,  and  requires  a  comparatively  high 
wind  in  which  to  start.  This  fact  has  been  appreciated  for 
some  time  and  various  devices  have  been  invented  which 
would  automatically  vary  the  load  of  a  mill  according  to 
the  wind  velocity.  A  perfectly  acting  device  of  this  sort 
would  evidently  enable  the  mill  to  deliver  a  maximum 
possible  power  output  in  the  course  of  a  season,  the  mill 
always  operating  at  the  most  efficient  load  no  matter 
what  the  wind  velocity.  Unfortunately,  such  an  ideal 
device  has  not  been  made,  and  it  involves  mechanical 
difficulties  not  likely  to  be  surmounted  for  some  time  to 
come.  The  best  that  can  be  done  under  the  circumstances, 
therefore,  in  view  of  this  peculiar  characteristic  of  the  wind 


206  PRACTICAL  IRRIGATION  AND  PUMPING 

wheel,  is  to  select  a  pump  of  such  size  that  for  the  partic- 
ular wind  conditions  of  any  given  locality  the  mill  may  be 
expected  to  deliver  the  greatest  possible  quantity  of  water 
in  a  season.  The  selection  of  this  pump  size  involves  a 
rather  extended  series  of  calculations  and  comparisons, 
which  probably  may  best  be  illustrated  by  a  concrete 
example. 

The  Problem  of  Determining  Best  Diameter  of  Pump 
Cylinders,  Concrete  Case. — Let  it  be  supposed  that  it  is 
desired  to  know  what  pump  should  be  used  with  a  1 2-foot 
mill  of  the  same  type  used  in  the  experiments  from  which 
the  above  diagrams  were  deduced;  where  it  is  desired  to 
pump  water  from  a  depth  of  40  feet  and  discharge  it  into 
a  reservoir  6  feet  deep.  Assuming  a  draw-down  of  5  feet 
and  a  friction  head  of  3  feet,  the  total  head  to  be  pumped 
against  would  be  40  +  6  +  5  +  3  =  54  feet. 

The  following  work,  upon  which  will  be  based  the  de- 
termination of  the  most  effective  pump  size,  will  rest  upon 
certain  published  results  of  Professor  Murphy  on  a  12 -foot 
mill,  to  which  he  attached  a  friction  brake  in  such  a  way 
that  the  performance  of  the  wheel  at  different  brake  loads 
and  at  different  wind  velocities  could  be  accurately  de- 
termined. These  results,  which  give  the  actual  power  of 
the  wheel,  can  be  used  for  a  comparison  of  direct  stroke  and 
geared  mills  as  well.  The  diagrams  which  follow  are  de- 
rived from  the  results  and  diagrams  given  by  the  authority 
mentioned.  Diagram  27  gives  the  relation  between  wind 
velocity  and  the  revolutions  per  minute  of  the  wind  wheel 
for  different  loads  as  expressed  by  the  number  of  foot-pounds 
of  work  accomplished  per  one  revolution  of  the  wind 
wheel. 

The  Size  of  Pump  for  Direct-Acting  Mill.— Windmills 
are  usually  arranged  for  different  lengths  of  pump  stroke, 
and  for  the  present  example  for  a  1 2-foot  mill  this  will  be 


WINDMILLS 


207 


taken  at  10  inches.  The  sizes  of  pump  cylinder  from  which 
a  selection  may  be  made  are  assumed  as  of  diameters  of 
4,  5,  6,  and  7  inches,  for  the  direct-stroke  mill.  A  slip  of 
15  per  cent,  will  be  assumed  for  the  pump,  which  value 
would  represent  one  in  very  good  condition,  and  a  mechan- 
ical efficiency  of  80  per  cent,  for  the  mill  that  is,  80  per 

12  FT.  STEEL  '"'POWER"  WINDMILL 


8      10     12     14     16     18      20     22     24 
Wind  Velocity  .  Miles  per  Hour 


DIAGRAM   27 

cent,  of  the  possible  work  of  the  wheel  will  be  assumed  as 
available  at  the  pump.  Using  the  value  for  slip  just  men- 
tioned, the  following  table  shows  the  capacity  of  different 
diameters  of  pump  cylinder  in  acre-feet  per  hour  at  differ- 
ent numbers  of  strokes  per  minute: 


208  PRACTICAL  IRRIGATION  AND  PUMPING 

TABLE  XI 

CAPACITY  OF  DIFFERENT  SIZES  OF  PUMP  CYLINDERS,  WITH 
15  PER  CENT.  SLIP 

ACRE-FEET  PER  HOUR 


Pump 

Strokes  per  Minute 

2O 

30 

40 

50 

60 

70 

80 

7x10  inches  

.0052 
.0038 
.O027 
.OOI7 

.0078 
.0057 
.0039 
.0025 

.0104 
.0076 
.0054 
.0034 

.0130 
.0095 
.0065 
.0042 

.0156 
.0114 
.008l 
.0051 

.0182 

•0133 
.0091 
.0059 

.0208 
.0152 
.OIO8 
.0068 

6  x  10  inches  

5x10  inches 

4x10  inches  

It  is,  of  course,  obvious  that  the  higher  speeds,  that  is, 
those  much  above  40  strokes  per  minute,  are  impracticable, 
owing  to  severe  inertia  effects.  The  whole  range  of  speed 
indicated  will,  however,  be  used  for  illustration. 

Using  the  sizes  of  cylinders  above  given,  the  following 
table  gives  the  foot-pounds  developed  per  revolution  of 
wind  wheel  for  a  54-foot  total  lift  with  15  per  cent,  slip  and 
80  per  cent,  mechanical  efficiency. 

TABLE  XII 

FOOT-POUNDS   OF   WORK   PER   ONE   REVOLUTION   OF   WlND   WHEEL 


Size  of  Pump 

4  x  10  ins. 

5  x  10  ins. 

6  x  10  ins. 

7x10  ins. 

8  x  10  ins. 

Ft.-lbs.     per 

rev  . 

260 

430 

58o 

800 

1,050 

Using  the  values  of  foot-pounds  per  revolution  of  wind 
wheel  as  an  argument,  we  may  now  by  use  of  Diagram  27 
determine  the  wind  velocity  which  is  necessary  to  give  the 
required  speed  of  the  wind  wheel.  These  values  are  shown 
in  the  following  table: 


WINDMILLS  209 

TABLE   XIII 
TWELVE-FOOT  DIRECT-STROKE  MILL 

WIND  VELOCITIES  IN  MILES  PER  HOUR  WHICH  WILL  TURN  WIND  WHEEL 

AT  VARIOUS  SPEEDS  WHEN  USING  VARIOUS  SIZES  OF 

PUMP  CYLINDERS 


Size  of  Pump 

Revolutions  of  Wind  Wheel  per  Minute 

20 

30 

40 

50 

60 

70 

80 

7  x  10  inches  

17 
14 
II-5 

9 

19 
15-5 
13-5 
ii 

20 
I? 
15 
12.6 

22 
18.5 
16.5 

14-5 

24 
20.5 

i8-5 
17 

6  x  10  inches  

23-5 
20 

20 

25 

5  x  10  inches 

4x10  inches  

Using  the  values  of  wind  velocity  as  above  given,  we  now 
refer  to  the  weather  records  and  determine  the  number  of 
hours  per  season  during  which  these  velocities  are  found 
to  occur.  These  are  shown  in  the  following  table: 

TABLE  XIV 

SHOWING  NUMBER  OF  HOURS  PER  SEASON  DURING  WHICH  WIND  WHEEL 
WILL  ROTATE  AT  GIVEN  SPEED  WITH  GIVEN  LOAD 

TWELVE-FOOT  DIRECT-STROKE  MILL 


Revolutions  of  Wind  Wheel  per  Minute 


Size  of  Pump 

20 

30 

40 

50 

60 

70 

80 

7  x  10  inches      ..... 

653 

653 

653 

4^0 

4^0 

6  x  10  inches 

044 

044- 

653 

6S3 

653 

4^0 

c  x  10  inches 

04.4. 

Q44 

044 

6<n 

653 

470 

4x10  inches  .  

I,l87 

Q44 

044 

944 

653 

653 

430 

NOTE. — The  blank  spaces  in  each  of  the  last  two  tables  indicate 
that  the  wind  velocities  are  above  25  miles  per  hour,  at  which  velocity, 
ordinarily,  mills  are  supposed  to  be  thrown  out  of  action  by  the  govern- 
ing device  to  prevent  injury  to  the  mill  and  tower. 


2IO 


PRACTICAL  IRRIGATION  AND  PUMPING 


If  the  number  of  hours  during  which  a  certain  wind 
velocity  occurs  be  now  multiplied  by  the  average  hourly 
discharge  in  acre-feet,  for  the  pump  speeds  corresponding 
to  that  load  and  wind  velocity,  we  may  construct  therefrom 
the  following  table: 

TABLE  XV 

TWELVE-FOOT  DIRECT-STROKE  MILL.    54-FEET  TOTAL  HEAD 
AVERAGE  QUANTITIES  PUMPED  PER  SEASON  IN  ACRE-FEET 


Hours  r 

>er  Season 

Size  of  Pump 

1,187 

944 

653 

430 

Totals 

7x10  inches 

5.  1 

6.1 

112 

6  x  10  inches  

4-5 

6.2 

5-7 

l6.4 

5  x  10  inches  

v3-7 

4.7 

7.0 

12    T> 

4x10  inches 

I    0 

T>.2 

7.  c: 

2.Q 

II    5 

The  fact  now  becomes  apparent,  as  seen  from  an  inspec- 
tion of  the  total  quantities  pumped  in  a  season,  given  in 
the  last  column  of  the  above  table,  that  the  6-  by  lo-inch 
pump  is  much  the  most  efficient  size  to  use,  since  by  it, 
under  the  local  conditions  of  wind  movement  and  head 
pumped  against,  the  largest  quantity  of  water  is  delivered. 
As  a  matter  of  fact,  this  would  have  to  be  modified  in  the 
practical  case,  since  if  a  pump  of  this  stroke  and  diameter 
were  used,  the  mill  would  have  to  be  arranged  to  cut  out  at 
lower  wind  velocities  to  avoid  the  danger  of  operation  at 
high  pump  speeds  for  considerable  periods.  If  this  size  of 
pump  were  used  and  it  were  proposed  to  prevent  the  pump 
from  operating  over  50  strokes  per  minute,  then,  as  shown 
by  the  above  table  of  wind  velocities  versus  loads  and 
speeds,  Table  XIII,  the  governor  would  have  to  be  adjusted 
to  throw  the  mill  out  of  action  at  wind  velocities  of  over 


WINDMILLS  211 

19  miles  per  hour.  This  limitation  on  rotative  speed  would 
cause  a  loss  of  5.7  acre-feet  per  season  with  the  6-  by  zo-inch 
pump,  4.4  acre-feet  for  the  5-  by  lo-inch,  and  6.4  acre-feet 
for  the  4-  by  lo-inch.  The  relative  quantities  pumped 
per  season  would  then  be  shown  by  the  following  table: 

TABLE  XVI 
TWELVE-FOOT  DIRECT-STROKE  MILL.    54-FEET  TOTAL  HEAD 


Size  of  pump.  .  .  . 
Acre-ft.  per  season 

7  x  10  ins. 

II.  2 

6  x  10  ins. 
10.7 

5  x  10  ins. 
7-9 

4x10  ins. 
5-1 

Upon  this  basis  it  appears  that  there  is  but  little  differ- 
ence between  the  7-  by  lo-inch  and  the  6-  by  lo-inch  pumps. 
Doubtless  an  investigation  similar  to  the  preceding  for 
pumps  of  different  strokes  would  show  some  combination 
of  stroke  and  diameter,  which,  without  exceeding  the  safe 
pump  speed,  would  give  a  greater  seasonal  capacity  than 
that  just  found.  One  fact  shown  by  the  above  tables  con- 
firms that  already  well  known  by  pump  and  windmill 
manufacturers  and  those  who  have  investigated  the  per- 
formance of  windmills,  namely,  that  the  direct-stroke  mill 
is  best  adapted  to  localities  where  the  average  wind  ve- 
locity is  high  and  of  long  duration. 

Size  of  Pump  for  Geared  Mills. — The  same  methods 
and  the  same  data  will  be  taken  for  this  example  as  in  the 
preceding  investigation  for  the  direct-stroke  mill.  It  is 
understood  that  in  the  geared  type  of  mill  the  pump  is 
driven  by  a  pitman  and  pump  rod  connected  to  a  crank 
shaft  which  rotates  at  less  speed  than  the  main  shaft  to 
which  the  wind  wheel  is  attached.  The  speed  reduction 
varies  with  different  makers,  but  in  the  present  case  the 
speed  of  the  pump  shaft  will  be  taken  at  one-third  the 


212  PRACTICAL  IRRIGATION  AND  PUMPING 

speed  of  the  main  shaft.  Then  the  number  of  pump  double 
strokes  will  be  one-third  the  revolutions  of  the  wind  wheel. 
The  introduction  of  the  gearing  thus  necessary  causes 
a  friction  loss  both  in  the  gearing  and  in  the  journals  so 
that  60  per  cent,  of  the  power  possible  from  the  wind 
wheel  will  be  assumed  in  this  case  as  being  available  at  the 
pump.  For  this  investigation  a  greater  number  of  pump 
diameters  will  be  considered,  but  of  the  same  stroke  with 
one  exception.  The  table  on  page  '2 13  gives  the  sizes  of 
pumps  which  will  be  tried,  together  with  the  foot-pounds 
of  work  corresponding  to  one  revolution  of  the  wind  wheel, 
for  a  total  pumping  head  of  54  feet. 

Averaging  the  acre-feet  discharged  over  the  range  of 
wind  velocities  which  occur  for  the  same  number  of  hours 
per  season  and  adding  together  the  discharges  for  the 
several  ranges,  we  obtain  the  total  for  the  season.  The 
8"  x  10"  pump  is  found  upon  this  basis  to  give  the 
maximum,  for  wind  velocities  below  25  miles  per  hour. 

By  referring  to  the  discussion  of  the  direct-stroke  mill, 
it  will  be  seen  that  for  the  weather  conditions  of  the  ex- 
ample the  difference  between  the  performance  of  the  direct 
and  geared  mills  in  this  instance  is  not  striking.  Placing 
the  results  side  by  side,  we  have. 

Direct  Stroke.  Geared. 

Size  of  cylinder 7  x  10  ins.  8  x  10  ins. 

Water-pumped  acre-feet  per 

season 11.2  10.5 

Both  mills  would  be  adjusted  to  be  thrown  out  of 
action  at  a  wind  velocity  of  about  25  miles.  While  there 
is  a  slight  advantage,  as  above  shown,  for  the  direct-stroke 
mill,  it  is  to  be  understood  that  this  is  due  to  the  relatively 
high  average  wind  velocity.  For  localities  with  lower 
average  wind  velocities  the  advantage  would  be  quite 


WINDMILLS 


213 


CO 

G 

04           vg 

j 

X          °° 

u 
Ea 

o 

CO 

G 
0           0 

Q 

X           ^ 

§ 

o 

§ 

1 

a.' 
c/) 

O          ^0 

1 

X 

00 

w 

1 

CO 

Q 

O           %$ 

1 

X 

-1    g  ft 

^  ^    o  j 

>  *s  ffi  • 

CO 

2     1 

w^  ^  g 

X 

PM    fl\     w   ^ 

VO 

s%  ?  « 

1 

"  1 

2      °° 

g 

X 

fc 

»o 

1 

o 

1 

| 

G 

w 

'5 

0 

^ 

c/5 

> 
™ 

fa 

o 

a       o 

1  ! 

1 

U 

o        r^ 
a;        *T 

.2        <J 

x        -. 

10 

ON 

o 

-. 

»o 

\^ 

^^ 

^- 

00 

° 

8 

° 

8- 

o 

0 

O 

1 

i 

i 

1 

to 

o 

o 

3 

00 
fO 

«o 

00 

8 

00 

5 

8 

8 

8 

8- 

0 

0 

Th 

s 

M 

VO 

10 

3 

»o 

8- 

8- 

. 

8- 

8 

o 

i 

00 

rj- 

g. 

8 

i 

I 

! 

8 

8 

)ujA\  jo  suor 

* 

VO 

8 

I 

8 

i 

rf 

s 

I 

3 
1 

8 

CO 

3 

o 

CO 

8 

8 

§ 

1 

1 

8 

vO 

10 

ct 

8 

8 

(N 

8 

8 

8 

1 

to 

3 

to 

CO 

^ 

C< 

3 

g 

8. 

8 

8 

8 

8 

& 

1 

j 

vO 

0 

IO 

M 

8 

§ 

8 

8 

8 

8 

a, 

3 

£ 

•8 

8 

| 

CO 

<U 

J3 

1 

CO 

^3 

o 

2  inches  .  . 

0 

O 

0 

0 

M 

N 

hH 

W 

H< 

^ 

M 

x 

*" 

X 

X 

X 

X 

00 

O 

0 

214 


PRACTICAL  IRRIGATION  AND  PUMPING 


a 
I 


W    H 

£  2 


;•  > 

§  §  § 

04gH 
*        2 

SgS 


IM 

s  S 


^  o 

o 

so 


JO   3ZJS 


10  O    O  10  O    ON 

N  »-i  W 


1010        t-i 


NH     r}-    1-4  P< 


: 


O      U.  O      >-  O 


HHTi- 


Hi-3-n- 


oo    t^          .  oo    «         «  oo    10 

M        .  00      «•  "I        ' 


•    00     CN  00 


•sui  oi  x  S     'sui  oi  x  9     'sut  oi  x  i 


WINDMILLS 


215 


o   ^t- 

co    rf 


ON  CO  10     CO  O  VO 

i-i  lO  rf     M  CO  »O 

vO  -^-   • 


1-1  O  CO    CO  O  O 


ON   •         VO    • 
CO  Tf 


**  °  § 

•<*•  • 
CO 


O     Is*  co  vO  O  ^O  O 

n    i-i  10  ^  n  10  ci 

\O  .       vQ 

CO  CO  TJ- 


corj-io          vOco^J-  ONCOO 

—     TriO  i-iiot^  i-iioco 


>O    rh   lO  00     CO  ON 

f-c       Tj-     Tt  M       IO  O 

ON      •                   vO  • 

f^  <N 


—  ^OO  Tt-^00  t^COVO 

—  Tt-OI  »-"TJ-ON  wiOvO 


!    c 


l 


•suyoixg    'suioixoi 


2l6  PRACTICAL  IRRIGATION  AND   PUMPING 

marked  in  favor  of  the  geared  mill.  While  the  foregoing 
analysis  is  long  and  tedious,  it  is  of  some  advantage  to  know 
that  even  for  a  windmill  there  is  a  feasible  method  of  cal- 
culating its  optimum  working  conditions  and  proportion- 
ing the  parts  of  the  machine  to  fulfil  those  conditions.  At 
present  most  calculations  of  windmill  capacity  are  based 
on  an  estimated  average  wind  velocity  acting  eight  hours  a 
day.  Since  the  average  assumed  is  generally  high,  and  the 
time  during  which  it  is  assumed  to  last  is  more  than  is 
customarily  encountered,  the  quantities  pumped  according 
to  manufacturers'  estimates,  are  generally  far  in  excess  of 
that  actually  realized.  It  would  seem  that  there  is  an 
opportunity  for  windmill  manufacturers  more  generally  to 
publish  authoritative  tests  from  which,  when  properly 
worked  out,  the  average  man  who  is  going  to  put  in  a  mill 
would  have  some  guidance  toward  the  selection  of  the  right 
size  of  wheel  and  pump  cylinder  to  give  the  optimum  service. 
The  Pump  Cylinder. — The  character  of  the  pumping 
portion  of  the  windmill  plant  will  vary  with  the  kind  of 
well  from  which  the  water  is  taken.  For  shallow  depths, 
say  30  feet  or  less,  the  open  well  is  much  to  be  preferred, 
and  in  this  well  will  be  used  an  ordinary  pump  cylinder, 
discharging  probably  through  a  length  of  spiral  riveted 
galvanized  pipe  to  an  outflow  pipe  at  the  surface.  The 
pump  cylinders  in  sizes  up  to  8-inch,  are  most  usually  of 
brass,  above  that  of  cast  iron,  and  the  valves  are  usually  of 
the  common  leather  flap  type.  For  deeper  wells  where 
water  is  encountered  at  depths  below  30  feet,  the  driven 
well  is  usually  necessary,  and  this  should  always  be  pro- 
vided with  an  ample  strainer,  preferably  of  as  open  a  type 
as  the  character  of  the  material  will  allow.  The  use  of 
drive  points  is  to  be  discouraged,  owing  to  the  limited 
capacity  and  the  imminent  possibility  of  early  clogging 
and  complete  stoppage  of  flow. 


WINDMILLS  217 

Where  the  driven  well  is  necessary,  the  best  scheme  is 
to  use  a  drive-pipe  of  such  size  as  will  allow  the  couplings 
of  a  pipe  of  the  same  nominal  size  as  the  pump  to  be  used 
to  pass  freely  into  and  through  the  drive-pipe.  Thus  the 
couplings  on  8-inch  pipe  have  a  nominal  diameter  of 
couplings  of  9.19  inches,  thus  making  it  necessary  to  use 
a  jo-inch  pipe.  The  pump  cylinder  is  attached  to  the 
bottom  of  a  "drop  pipe"  of  the  same  nominal  diameter, 
and  is  lowered  into  the  well  section  by  section,  the  pump 
rods  being  connected  as  it  goes.  This  enables  the  pump 
cylinder  to  be  withdrawn  when  the  valves  need  replacing 
or  the  piston  needs  repacking.  In  cheap  installations  and 
for  small  wells  the  rough  drive-pipe  itself  is  sometimes 
made  to  serve  as  a  cylinder  or  working  barrel  and  no  "drop 
pipe"  is  used.  Again,  a  thin  brass  lining  is  sometimes 
inserted  in  the  well-casing  and  fastened  at  the  desired 
depth  by  rubber  rings  or  wedges,  which  it  is  difficult,  if  not 
impossible,  ever  to  remove  after  once  being  placed.  Such 
pumps,  while  cheap,  cannot  be  considered  as  lasting,  and 
when  they  do  wear  out,  the  well  is  practically  useless, 
since  it  is  extremely  difficult  to  remove  the  bottom  valve, 
and  equally  difficult  to  replace  a  brass  liner. 

For  the  deep  bored  or  driven  well,  therefore,  it  is  recom- 
mended that  a  unit  working  barrel  be  employed,  of  a  size 
suited  to  the  load  which  an  investigation  of  the  wind  char- 
acteristics of  the  locality  indicates  may  be  used,  and  that 
this  " working  barrel"  be  attached  to  a  "drop  pipe"  of  the 
same  nominal  diameter  held  rigidly  at  the  surface.  At  the 
surface,  the  drop  pipe  is  generally  screwed  into  a  tee  and  a 
nipple  placed  above  it  of  sufficient  length  to  insure  that 
there  will  be  enough  head  to  force  water  out  through  the 
outlet  connected  to  the  side  branch  of  the  tee.  Water 
may  be  carried  under  pressure  to  a  point  some  distance 
away  by  this  method,  without  the  use  of  a  stuffing  box. 


2l8  PRACTICAL  IRRIGATION  AND   PUMPING 

For  deep  wells,  a  working  barrel  provided  with  ball  valves 
is  frequently  preferred  to  the  leather  flap  or  metallic  valve 
type  of  the  ordinary  cone  seat.  The  writer  knows  of  one 
instance  in  his  own  experience  of  such  a  cylinder  working 
perfectly  for  more  than  five  years  under  nearly  loo-foot 
head. 


APPENDIX 

Partial  list  of  manufacturers  and  dealers  in  machinery  and  appliances 
used  in  irrigation  pumping. 

CENTRIFUGAL  PUMPS 

All  is- Chalmers  Manufacturing  Company,  Milwaukee,  Wis. 

American  Well  Works,  Aurora,  111. 

Buffalo  Steam  Pump  Company,  Buffalo,  N.  Y. 

Byron  Jackson  Machine  Works,  San  Francisco,  Cal. 

De  Laval  Steam  Turbine  Works,  Trenton,  N.  J. 

Krogh  Manufacturing  Company,  San  Francisco,  Cal. 

Lawrence  Machine  Company,  Lawrence,  Mass. 

R.  D.  Wood  &  Company,  Philadelphia,  Pa. 

Henry  R.  Worthington,  New  York,  N.  Y. 

PISTON  AND  PLUNGER  PUMPS 

American  Well  Works,  Aurora,  111. 

Cook  Well  Company,  St.  Louis,  Mo. 

Deming  Company,  Salem,  Ohio 

Fairbanks  Morse  &  Company,  Chicago,  111. 

Goulds  Manufacturing  Company,  Seneca  Falls,  Mass. 

Keystone  Pump  Manufacturing  Company,  Beaver  Falls,  Pa. 

WOOD  STAVE  PIPE 

Pacific  Tank  and  Pipe  Company,  San  Francisco,  Cal. 
Washington  Pipe  and  Foundry  Company,  Tacoma,  Wash. 
Redwood  Manufacturers  Company,  San  Francisco,  Cal. 
Portland  Wood  Pipe  Company,  Portland,  Ore. 

SPIRAL  AND  STRAIGHT  RIVETED  PIPE 

American  Spiral  Pipe  Works,  Grant  Works,  111. 
Merchant  &  Evans  Company,  Philadelphia,  Pa.     (Spiral.) 
Power  &  Mining  Machinery  Company,  Cudahy,  Wis. 
Tofts  Structural  Iron  Works,  Houston,  Texas. 
Union  Iron  Works,  San  Francisco,  Cal. 
Weigele  Riveted  Steel  Pipe  Works,  Denver,  Colo. 
Western  Pipe  &  Steel  Company,  Los  Angeles,  Cal. 
219 


220  APPENDIX 

VALVES  AND  FITTINGS 

Crane  Company,  Chicago,  Salt  Lake  City,  etc. 

Wm.  Powell  Company,  Cincinnati,  Ohio. 

Chapman  Valve  Manufacturing  Company,  Indian  Orchard,  Mass. 

GATES  AND  CONTROLLING  APPLIANCES 

Hinman  Hydraulic  Manufacturing,  Denver,  Colo. 
Coffin  Valve  Company,  Boston,  Mass. 

WELL  DRILLING  MACHINERY  AND  APPARATUS 
American  Well  Works,  Aurora,  111. 
Keystone  Driller  Company,  Beaver  Falls,  Pa. 
Williams  Brothers,  Ithaca,  N.  Y. 

GASOLINE  ENGINES 

Dempster  Mill  Manufacturing  Company,  Beatrice,  Neb. 

Fairbanks  Morse  &  Company,  Chicago,  111. 

International  Harvester  Company,  Chicago,  111. 

Otto  Gas  Engine  Works,  Philadelphia,  Pa. 

Stover  Engine  Works,  Freeport,  111. 

Witte  Iron  Works  Company,  Kansas  City,  Mo. 

OIL  ENGINES 

American  Diesel  Engine  Company,  St.  Louis,  Mo. 

De  La  Vergne  Machine  Company,  New  York,  N.  Y. 

Elyria  Engine  Company,  Elyria,  Ohio. 

Fairbanks  Morse  &  Company,  Chicago,  111. 

Mietz  Iron  Foundry  &  Machine  Works,  New  York,  N.  Y. 

Western  Gas  Engine  Works,  Los  Angeles,  Cal. 

GAS  PRODUCERS 

Fairbanks  Morse  &  Company,  Chicago,  111. 

Minneapolis  Steel  and  Machinery  Company,  Minneapolis,  Minn. 

Rathbun  Jones  Engineering  Company,  Toledo,  Ohio. 

Weber  Gas  and  Gasoline  Engine  Company,  Kansas  City,  Mo. 

Westinghouse  Machine  Company,  Oil  City,  Pa. 

R.  D.  Wood  &  Company,  Philadelphia,  Pa. 

ELECTRIC  MOTORS  AND  ELECTRICAL  APPLIANCES 

Allis-Chalmers  Manufacturing  Company,  Milwaukee,  Wis. 

Fairbanks  Morse  &  Company,  Chicago,  111. 

General  Electric  Company,  Schenectady,  N.  Y. 

Reliance  Electrical  Company,  St.  Louis,  Mo. 

Wagner  Electric  Manufacturing  Company,  St.  Louis,  Mo. 

Westinghouse  Electric  and  Manufacturing  Company,  Pittsburg,  Pa. 


APPENDIX  221 

GENERAL  CONTRACTORS  FOR  COMPLETE  PLANTS 

Allis-Chalmers  Manufacturing  Company,  Milwaukee,  Wis. 
Fairbanks  Morse  &  Company,  Chicago,  111. 
Hendrie  &  Boltoff,  Denver,  Colo. 
Krakauer,  Zork  &  Moye,  El  Paso,  Texas. 

Mine  and  Smelter  Supply  Company,  Denver,  Salt  Lake  City,  El 
Paso. 


INDEX 


Acre-foot,  I 

Acre-inch,  I 

Acres  per  day  irrigated,  8 

Alfalfa  irrigation,  4 

Allowance  per  acre,  pumped  water, 

9 

Amount  of  water  at  each  irriga- 
tion, 5 

Artesian  wells,  13 
Artesian  well  casing,  54 
Attendance,  150 

B 

Belt  drive,  1 14 

vertical  shafts,  126 
Boilers,  167 

insurance,  168 
Borrow  pit,  162 


Capacity,  artesian  field,  17 

Capacity  of  wells  vs.  days  pump- 
ing, 31 

Central  station  plants,  locations 
suitable  for,  185 

Central  station  pumping,  185 
in    connection  with  beet-sugar 

or  canning  factory,  195 
ownership  of  tract,  193 

Centrifugal  pumps,  65 
bearings,  69 
characteristics  of,  71 
characteristic  curves,  76 
costs  of  three  small  sizes,  97 
depreciation,  small  sizes,  98 


Centrifugal  pumps,  flexible  coup- 
lings, 70 

inspection  and  tests,  70 

impeller,  69 

location  and  conditions  suitable 
for,  105 

loss  of  power,  100 

multi-stage,  107 

packing  joint  and  clearance,  69 

pump  builders'  diagrams,  95 

pump  case,  67 

shaft,  69 

size  of  engine  or  motor-drive,  93 

selection  of,  86 

specifications  for,  66 

speed,  91 

speed,  efficiency,  and  head  vs. 
discharge,  93 

stuffing  boxes,  69 

suction  opening,  69 
Condensers,  167 
Continuous  flow, 

disadvantages  as  compared  with 

intermittent  flow,  12 
Contract  for  continuous  flow,  12 
Cook  strainer,  43 
Corn,  sorghum,  Kaffir  corn,  irriga- 
tion, 5 

Cost  and  profit  on  small  farm,  152 
Cost  of  electric  power,  97 

operation,  155 

pumping,  135 

factors  affecting  cost  of,  136 

reservoir,  161 

total    estimated,    driven    well, 
deep  pit,  electrical  plants, 

154 

Crude   oil   and   distillates   power 
cost,  142 


223 


224 


INDEX 


Deep-well  pumps, 

capacity  limited,  133 

important  details,  134 

speed,  133 

Depreciation  table,  149 
Depth  of  strainer,  37 
Diesel  engine,  179 
Discharge  pipe,  112 
Distillates,  175 
Diversified  crops,  188 
Division    of    acreage    on    small 

farm,  155 
Draw-down,  23 

limits,  33 
Drive  pipe,  217 

Driven  wells,  relative  capacity,  34 
Dry-farming  by  windmills,  197 
Dry-farming    methods  an  aid  to 

irrigation,  10 
Duplex  and  triplex  pumps,  130 

advantages  and  efficiency,  132 

capacity,  130 

vertical  rods,  132 
Duty  of  pumped  water,  10 
Duty  of  water,  I 

various  crops,  3 


Effective  size,  sand  grain,  31 

Efficiency  of  pump,  73 

Ejector  primer,  1 1 1 

Electric  drive,  the  ideal  arrange- 
ment, 121 

Electric  motor  drive,  183 

Electric  motors,  direct  or  belt 
connected  to  pump,  184 

Electrical  pumping  plants,  skilled 
attendance  necessary,  151 

Electrically  driven,  vertical,  cen- 
trifugal pump,  127 

Electricity,  power  costs,  14/1 

End  thrust,  124 


Fittings,  112-116 

Flat  rate,  146 

Flow  into  driven  well,  23 

Flow  of  underground  water,  20 

Foot  valve,  109 

Frequency,  145 

Frequency  meter,  145 

Friction  effect  in  suction  pipes  109 

Friction  head,  87-88 

in  pipe,  90 

Fuel  cost:  crude  oil  and  distillates, 
142 

hourly,  gasoline  engines,  140 
high-speed  steam  engines,  139 


Gasoline  engines,  169 

difficulties  in  operation  of,  170 

over-rating  of,  173 

power  cost,  140 
Gas  producer  and  engine,  180 
Gas    producer    plant,    conditions 
warranting  adoption  of,  182 
Geology  of  deep  wells,  16 
Geology  of  shallow  wells,  17 
Grain  crops,  irrigation,  4 
Ground  water,  level  of,  18 

surface,  21 

H 
Head,  190 

total,  meaning  of  term,  87 
Hornsby-Akroyd  type  engine,  178 
Humphrey  gas  pump,  60 
Hydraulic  gradient,  16 
Hydrostatic  head,  87 

I 

Impellers,  64 
Induction  motors,  183 

provision  for  ventilation,  184 

slip  ring,  183 


INDEX 


225 


Installation  for  centrifugal  pumps, 

types  of,  1 08 

Interest  and  depreciation,  146 
Interference  of  wells,  32 
Irrigating  stream,  best  size  of,  6 


Jetting  machines,  47 
Joints,  special  pipe,  55 

K 
Kerosene  as  fuel,  175 


Lane  strainer,  41 
Legal  considerations,  1 1 
Life  of  plant,  148 
Load  factor,  195 
Load  factor,  yearly,  188 
Low  lift  plant,  123 

M 

Magneto,  170 

Maintenance  and  repairs,  149 
Measurement  of  water,  means  of, 

129 
Motors,  slip  ring  and  squirrel  cage 

induction,  183 
synchronous,  184 

N 
Needle-valve  adjustment,  172 

O 
Oil  fuels,  174 

range  in  specific  gravity,  175 
Onions,    profit   in   raising,    under 

irrigation,  157 
Operation  of  well-sinking,  50 

P 

Peak  load,  194 
Peak-load  contracts,  145 


Pecos  Valley,  13 

Periods  of  irrigation,  4 

Pipe,  standard  sizes,  53 

Pipe  weights,  53 

Pit  lining,  115-51 

Porcher  strainer,  41 

Porosity,  water-bearing  material, 

Power  cost,  electricity,  144 
producer  gas,  143 

Power  requirement,  determined  by 
head  and  quantity  pumped, 
136 

Prime  movers,  165 

Priming,  no,  125 

Problem  in  cost  and  profit,  demon- 
stration of,  154 

Producer-gas  plant,  suction  type, 
181 

Puddling  reservoirs  for  water- 
tightness,  161 

Pump  cylinder,  216 

Pump  equations,  99 

Pump  foundations,  1 16 

Pump  pit,  114 

limitation  in  depth,  107 

Pumping  in  Snake  River  Valley, 
xi,  196 

Pumping  season,  194 

Pumps,  proposed,  59 


Rate  of  flow,  underground  water, 

20 

Rates  for  electric  power,  97,  144 
Rating  of  windmills,  199 
Relative  capacity,  driven  wells,  34 
Reservoirs,  160 

capacity  of,  162 

construction  of,  161 
cost  of,  161 

depth,  163 

depth,  capacity,  cubic  yards  in 


226 


INDEX 


embankment,     etc.      (dia- 
gram),   164 

Reservoirs,    puddling  for    water- 
tightness,  161 

Riparian  rights,  1 1 

Rodents,  162 

Rope  transmission  of  power,  115 

Rotary  drilling  machines,  47-49 
in  operation,  52 


Saline  ingredients,  187 
Sand  grain,  effective  size,  31 
Sand    with    duplex    and    triplex 

pumps,  130 
Saturation  lines,  23 
Selection  of  pumps,  caution  needed, 

58 

Size  of  irrigating  stream,  8 
Size  of  pumping  plant  for  differ- 
ent acreages,  159 
Size  of  well  tube,  34 
Slip,  131 
Solar  oil,  176 

Specifications,  centrifugal  pump,  66 
Speeds,  pump  and  motor,  120 
Spudding  machine,  46 
Standard  types  of  pumps,  62 
Steam    consumption,     automatic 

engine,  138 

Steam  engines  and  boilers,  165 
Steam  engines,  fly-wheel  govern- 
ors, 1 66 
Steam  engines,  throttle  governed, 

166 

Step  bearing,  124 
Storage  of  flood  waters,  12 
Stovepipe  casing,  56 
Strainers,  37 

conclusions  on,  43 

depth  of,  37 

kinds  of,  40 

open,  44 

Suspension  frame,  124 
Synchronous  motors,  184 


Time  of  pumping,  equation,  27 
Transformer-room  equipment,  183 
Truck  garden  irrigation,  5 
Type  of  pump  to  use,  60 

U 

Underground  rivers,  19 
Underground   sources,  legal  con- 
siderations, 13 


Vacuum  gauge,  117 
Velocity  head,  87 
Ventilation  of  motors,  184 
Vertical    centrifugal    multi-stage 

pump,  65 
Voltage  for  primary  distribution, 

183 

W 

Water  hammer,  112 
Water  measurement,  means  of,  129 
Wattmeter,  curve  drawing,  145 
Well-drilling  machinery,  45 
Well  pit,  51 
Well  sinking,  45 

Windmills,  field  in  irrigation,  197 
governing,  199 

power    developed    at    different 
loadings  and  wind  veloci- 
ties, 204 
power  of,  201 
size  of  pump  for  direct  acting, 

207 
size  of  pump  for  geared  mills, 

211 

speed,  205 
Wind    records,   use    in    windmill 

studies,  202 
Wiring,  120 


Yields  and  profits,  table  of,  as- 
sumed, 156 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


AN  INITIAL  FINE  OP  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


•EC'D  LD 


01974  j 

CMC  t»T    I  OCT  8  1 74 


LD  21-100WI-12, '43  (8796s) 


30031 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


